These issues happened after todays content patch.

Issue #1:
x1 ...ates\lib\LibClassicCasterino\LibClassicCasterino-13.lua:482: table index is nil Stack: ...ates\lib\LibClassicCasterino\LibClassicCasterino-13.lua:482: in main chunk Time: 2019/09/24 20:36:13 Index: 1/6 RealUI Version: 2.1.0 Locals: MAJOR = "LibClassicCasterino" MINOR = 13 lib = <table> { casters = <table> {} UnitCastingInfo = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:238 callbacks = <table> {} RegisterCallback = <function> defined @RealUI_Bugs\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:90 movecheckGUIDs = <table> {} UnregisterCallback = <function> defined @RealUI_Bugs\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:153 frame = <unnamed> {} UnitChannelInfo = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:255 UnregisterAllCallbacks = <function> defined @RealUI_Bugs\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:174 } f = <unnamed> { 0 = <userdata> COMBAT_LOG_EVENT_UNFILTERED = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:134 UNIT_SPELLCAST_START = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_CHANNEL_START = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_DELAYED = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_CHANNEL_UPDATE = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_CHANNEL_STOP = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_STOP = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_INTERRUPTED = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 UNIT_SPELLCAST_FAILED = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:269 } callbacks = <table> { recurse = 0 events = <table> {} OnUsed = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:283 Fire = <function> defined @RealUI_Bugs\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:59 OnUnused = <function> defined @Kui_Nameplates\lib\LibClassicCasterino\LibClassicCasterino.lua:301 } casters = <table> {} movecheckGUIDs = <table> {} MOVECHECK_TIMEOUT = 4 UnitGUID = <function> defined =[C] bit_band = <function> defined =[C] GetTime = <function> defined =[C] CastingInfo = nil ChannelInfo = nil GetUnitSpeed = <function> defined =[C] COMBATLOG_OBJECT_TYPE_PLAYER = 1024 COMBATLOG_OBJECT_REACTION_FRIENDLY = 16 classCasts = <table> { 10468 = 1.500000 24239 = 1 10216 = 3 126 = 5 10605 = 2.500000 19943 = 1.500000 17923 = 1.500000 5784 = 3 25297 = 3.500000 759 = 3 9858 = 2 25307 = 3 25309 = 2 25311 = 2 688 = 10 17951 = 3 17953 = 3 982 = 10 20755 = 3 20757 = 3 6366 = 3 20773 = 10 17727 = 5 28270 = 1.500000 13819 = 3 25357 = 3 10140 = 3 3552 = 3 23214 = 3 10912 = 3 10054 = 3 8690 = 10 14327 = 1.500000 18658 = 1.500000 2641 = 5 1002 = 2 20904 = 3 12826 = 1.500000 9853 = 1.500000 1842 = 2 10623 = 2.500000 20777 = 10 556 = 10 691 = 10 9912 = 2 2645 = 3 6196 = 2 17924 = 4 25292 = 2.500000 17928 = 2 10934 = 2.500000 25298 = 3.500000 15208 = 3 4068 = 1 25304 = 3 25306 = 3.500000 6064 = 3 6201 = 3 10053 = 3 6202 = 3 25316 = 3 17952 = 3 23161 = 3 10947 = 1.500000 20752 = 3 10876 = 3 20756 = 3 2053 = 2.500000 15261 = 3.500000 10318 = 2 25314 = 3 10955 = 1.500000 10917 = 1.500000 20770 = 10 10207 = 1.500000 693 = 3 17728 = 5 10326 = 1.500000 28612 = 3 20748 = 2 28023 = 3 18960 = 10 9901 = 1.500000 11729 = 3 11730 = 3 6215 = 1.500000 11605 = 1.500000 2362 = 5 712 = 10 697 = 10 1122 = 2 18647 = 1.500000 11726 = 3 } classChannels = <table> { 13544 = 5 9863 = 9.500000 11700 = 4.500000 17402 = 9.500000 1515 = 20 126 = 45 11678 = 7.500000 12051 = 8 746 =

Issue #2:
x1 ...dOns\Kui_Nameplates\lib\LibClassicDurations-17\core.lua:147: table index is nil Stack: ...dOns\Kui_Nameplates\lib\LibClassicDurations-17\core.lua:147: in function 'Spell' ...ameplates\lib\LibClassicDurations-17\classAbilities.lua:71: in main chunk Time: 2019/09/24 20:36:13 Index: 2/6 RealUI Version: 2.1.0 Locals: id = 26635 opts = <table> { type = "BUFF" duration = 10 } lastRankID = 26635 spellName = nil (*temporary) = <table> { Free Action = 6615 Mind Amplification Dish = 13181 Goblin Rocket Boots = 8892 Shadow Reflector = 23132 Invulnerability = 3169 Freedom = 9774 Gnomish Rocket Boots = 13141 Running Speed = 9175 Goblin Mortar = 13237 Mithril Insignia = 12733 Damage Absorb = 23991 Recently Bandaged = 11196 Tidal Charm = 835 Spell Vulnerability = 23605 Restoration = 11359 Self Invulnerability = 16621 Thorium Grenade = 19769 Fire Reflector = 23097 Abolish Poison = 14253 Aura of Protection = 23506 Frost Reflector = 23131 The Burrower's Shell = 29506 Flash Bomb = 5134 Flee = 5024 Berserking = 23505 Reckless Charge = 13327 Sleep = 1090 Net-o-Matic = 16566 Dazed = 1604 Poison Mushroom = 6727 Living Free Action = 24364 Speed = 14530 } (*temporary) = "number" (*temporary) = nil (*temporary) = nil (*temporary) = nil (*temporary) = nil (*temporary) = "table index is nil" GetSpellInfo = <function> defined =[C] spellNameToID = <table> { Free Action = 6615 Mind Amplification Dish = 13181 Goblin Rocket Boots = 8892 Shadow Reflector = 23132 Invulnerability = 3169 Freedom = 9774 Gnomish Rocket Boots = 13141 Running Speed = 9175 Goblin Mortar = 13237 Mithril Insignia = 12733 Damage Absorb = 23991 Recently Bandaged = 11196 Tidal Charm = 835 Spell Vulnerability = 23605 Restoration = 11359 Self Invulnerability = 16621 Thorium Grenade = 19769 Fire Reflector = 23097 Abolish Poison = 14253 Aura of Protection = 23506 Frost Reflector = 23131 The Burrower's Shell = 29506 Flash Bomb = 5134 Flee = 5024 Berserking = 23505 Reckless Charge = 13327 Sleep = 1090 Net-o-Matic = 16566 Dazed = 1604 Poison Mushroom = 6727 Living Free Action = 24364 Speed = 14530 } spells = <table> { 3169 = <table> {} 23451 = <table> {} 29506 = <table> {} 11196 = <table> {} 4068 = <table> {} 14253 = <table> {} 26740 = <table> {} 11359 = <table> {} 1090 = <table> {} 23097 = <table> {} 25746 = <table> {} 25747 = <table> {} 25750 = <table> {} 13099 = <table> {} 19769 = <table> {} 23991 = <table> {} 16621 = <table> {} 5134 = <table> {} 5024 = <table> {} 6615 = <table> {} 9774 = <table> {} 2379 = <table> {} 8892 = <table> {} 13141 = <table> {} 16566 = <table> {} 9175 = <table> {} 6727 = <table> {} 13237 = <table> {} 13138 = <table> {} 24364 = <table> {} 12733 = <table> {} 23506 = <table> {} 13327 = <table> {} 23505 = <table> {} 1604 = <table> {} 23493 = <table> {} 835 = <table> {} 23131 = <table> {} 23132 = <table> {} 13181 = <table> {} 14530 = <table> {} 23605 = <table> {} }

Issue #3:

x1 ...dOns\Kui_Nameplates\lib\LibClassicDurations-17\core.lua:175: table index is nil Stack: ...dOns\Kui_Nameplates\lib\LibClassicDurations-17\core.lua:175: in function <...dOns\Kui_Nameplates\lib\LibClassicDurations\core.lua:170> SharedXML\C_TimerAugment.lua:16: in function <SharedXML\C_TimerAugment.lua:14> Time: 2019/09/24 20:36:18 Index: 4/6 RealUI Version: 2.1.0 Locals: dataTable = <table> { 28616 = 30 24713 = 3600 16587 = 600 7236 = 3600 7252 = 3600 14534 = 300 16843 = 4 7300 = 1800 21066 = 10 25289 = 120 17227 = 120 7396 = 30 14822 = 15 17483 = 6 17547 = 5 10855 = 10 10951 = 600 26121 = 8 15366 = 3600 15398 = 8 22666 = 6 22730 = 600 15494 = 10 7764 = 1800 7812 = 30 15654 = 18 7844 = 1800 19275 = 15 11719 = 30 15878 = 3 27721 = 3600 11879 = 5 8052 = 12 8068 = 1800 8100 = 1800 8116 = 1800 24394 = 3 16326 = 600 4101 = 6 16460 = 1800 20619 = 10 4149 = 10 2091 = 12 8392 = 10 12551 = 10 21067 = 10 8552 = 120 17292 = 30 543 = 30 17484 = 30 17548 = 3600 553 = 30 12967 = 15 30089 = 3600 8936 = 21 9032 = 30 18124 = 27 9128 = 120 9192 = 120 26634 = 604800 9256 = 10 22667 = 15 22731 = 27 22859 = 5 589 = 18 13543 = 5 18956 = 30 595 = 30 23179 = 1200 9576 = 10 4805 = 15 603 = 60 605 = 60 9736 = 30 27722 = 3600 9800 = 60 19660 = 60 9896 = 12 19852 = 300 24011 = 10 9992 = 10 24203 = 30 14183 = 10 20236 = 120 20300 = 10 14279 = 8 28618 = 1 24587 = 10 16461 = 1800 20620 = 300 16717 = 5 14535 = 300 10472 = 8 29194 = 120 21068 = 24 2651 = 15 17165 = 3 17293 = 8 5365 = 20 673 = 3600 5413 = 120 10856 = 8 10888 = 8 17741 = 60 10952 = 600 687 = 1800 689 = 5 18125 = 600 5573 = 8 699 = 5 22412 = 30 703 = 18 2819 = 12 707 = 15 709 = 5 18765 = 20 22924 = 10 18957 = 30 5781 = 30 23244 = 4 731 = 8 2947 = 180 5909 = 600 19597 = 900 745 = 10 16071 = 300 12040 = 30 755 = 10 16231 = 120 3043 = 20 20301 = 10 6117 = 1800 16359 = 30 8233 = 1.500000 24716 = 3 775 = 8 6213 = 15 6229 = 30 12520 = 4 785 = 20 3147 = 12 17038 = 1200 3163 = 3600 17230 = 300 8649 = 30 6405 = 180 3219 = 3600 25804 = 900 12968 = 15 13032 = 60 3267 = 7 6581 = 10 13224 = 15 829 = 30 833 = 10 835 = 3 837 = 6 839 = 30 18702 = 60 6741 = 20 3387 = 120 849 = 60 851 = 10 853 = 3 855 = 30 3427 = 300 6869 = 2 3443 = 15 863 = 60 865 = 8 867 = 30 13896 = 15 871 = 10 23885 = 8 877 = 30 7045 = 60 14120 = 30 885 = 120 3547 = 8 24333 = 2 7125 = 120 14280 = 8 28620 = 2 3603 = 15 10345 = 20 905 = 600 3627 = 12 3635 = 6 10473 = 8 3651 = 10 25165 = 15 29388 = 12 7365 = 30 3699 = 10 14888 = 1800 10857 = 35 3747 = 30 17743 = 120 10953 = 15 945 = 600 11113 = 6 7621 = 10 22478 = 15 11273 = 6 11305 = 15 22734 = 30 15656 = 15 23182 = 900 11657 = 20 15784 = 60 11721 = 300 15848 = 1800 23694 = 5 15976 = 10 19727 = 3600 23886 = 8 8037 = 8 8053 = 12 1009 = 5 16168 = 20 8101 = 1800 8117 = 1800 4067 = 2 20303 = 10 4083 = 30 28621 = 2 4102 = 15 20559 = 6 4134 = 10 1038 = 300 4166 = 3 8362 = 20 24974 = 12 12521 = 3 1058 = 12 1062 = 15 29325 = 25 8554 = 2 17168 = 10 8650 = 30 1086 = 1800 1090 = 30 1094 = 15 1098 = 300 25806 = 30 17680 = 60 12969 = 15 8938 = 21 1126 = 1800 1130 = 120 1138 = 60 22415 = 10 22479 = 6 29252 = 5 301100 = 3 22735 = 7200 19710 = 900 22863 = 10 31562 = 6 31466 = 1 9482 = 30 13951 = 20 23183 = 12 9578 = 10 31316 = 0.100000 13737 = 5 27534 = 6 19408 = 8 9738 = 120 29220 = 300 30918 = 1 9834 = 12 28011 = 120 9898 = 30 9930 = 30 27556 = 15 30805 = 10 28754 = 15 28825 = 8 30441 = 30 24335 = 12 24596 = 120 14275 = 20 28622 = 60 10250 = 30 20560 = 6 20624 = 3600 16593 = 120 30336 = 7200 1302 = 45 24975 = 12 29134 = 5 5254 = 30 18791 = 1800 30297 = 1800 5302 = 5 30285 = 15 30238 = 1800 29198 = 120 5366 = 20 30167 = 600 10794 = 30 30165 = 10 30113 = 30 10890 = 8 17745 = 10 25999 = 1 30112 = 2 17937 = 300 30110 = 604800 30109 = 5 30095 = 8 18193 = 600 30094 = 8 30092 = 8 30090 = 3600 11274 = 6 30088 = 3600 30082 = 3 22736 = 600 15497 = 4 1430 = 12 30081 = 300 15593 = 8 30080 = 300 5782 = 10 1450 = 1800 11328 = 3600 11658 = 15 1462 = 30 5862 = 1800 12097 = 20 23568 = 8 30002 = 6 23696 = 8 30001 = 8 1490 = 300 23888 = 8 5990 = 8 29998 = 21 12042 = 15 20223 = 10 29915 = 10 29910 = 1 24336 = 12 20305 = 30 16329 = 600 16361 = 1.5

You're using an alpha or one of the classic releases. Use 2.24 on retail (https://www.curseforge.com/wow/addons/kuinameplates/files/2730194)