On 1.6 having a lockbox on yoru bag results in an error. Rogue lvl is above the necessary for this particular lockbox:

Rogue lvl 65 (lockpicking skill is the same as the lvl)
Item ID is 43622, Froststeel Lockbox qhich requires lockpicking (30)

Error given by verbose mode:

[12:21:11] [NOP] ItemGetItem: itemID 186710 rejected by map use
[12:21:12] [NOP] ItemGetItem: itemID 186710 rejected by map use
[12:21:12] BugSack: There's a bug in your soup!
[12:21:21] [NOP] ItemGetItem: itemID 186710 rejected by map use
[12:21:41] [NOP] ItemGetSpell: itemID 113558 spell Learning
[12:21:41] [NOP] ItemToUse: itemID 113558 count 1 prio 2 zone nil map nil aura nil source SPELL
[12:21:41] [NOP] ItemGetItem: itemID 186710 rejected by map use
[12:21:41] BugSack: There's a bug in your soup!

And this is from bug grabber

18x NOP/nop-item.lua:105: attempt to call method 'GetText' (a nil value)
[string "@NOP/nop-item.lua"]:105: in function ItemGetLockPattern' [string "@NOP/nop-item.lua"]:127: in function ItemGetPattern'
[string "@NOP/nop-item.lua"]:229: in function ItemScan' [string "@NOP/nop-item.lua"]:409: in function ?'
[string "@ElvUI_Libraries/Core/Ace3/AceTimer-3.0-17/AceTimer-3.0.lua"]:55: in function <...UI_Libraries/Core/Ace3/AceTimer-3.0/AceTimer-3.0.lua:50>
Locals:
self =

{
pickLockSpell = "Pick Lock"
modules = {
}
CancelTimer = defined @ElvUI_Libraries/Core/Ace3/AceTimer-3.0/AceTimer-3.0.lua:147
QBQuestAccept = defined @NOP/nop-quest.lua:268
LOOT_SPEC = defined @NOP/nop-events.lua:121
ItemGetItem = defined @NOP/nop-item.lua:64
ButtonOnDragStop = defined @NOP/nop-button.lua:186
SetDefaultModulePrototype = defined @ElvUI_Libraries/Core/Ace3/AceAddon-3.0/AceAddon-3.0.lua:405
ItemGetLockPattern = defined @NOP/nop-item.lua:99
ActionButton_ShowOverlayGlow = defined @NOP/nop-button.lua:421
QBAnchor = defined @NOP/nop-quest.lua:71
IsEnabled = defined @ElvUI_Libraries/Core/Ace3/AceAddon-3.0/AceAddon-3.0.lua:447
SpellLoad = defined @NOP/nop-core.lua:225
ScheduleTimer = defined @ElvUI_Libraries/Core/Ace3/AceTimer-3.0/AceTimer-3.0.lua:94
QBButton = defined @NOP/nop-quest.lua:88
ProfileLoad = defined @NOP/nop-profile.lua:25
Zone = "Ahava's Garrison"
PLAYER_LOGIN = defined @NOP/nop-events.lua:140
InitEvents = defined @NOP/nop-events.lua:49
ButtonReputation = defined @NOP/nop-button.lua:121
PrintTooltip = defined @NOP/nop-core.lua:277
ButtonHotKey = defined @NOP/nop-button.lua:356
ItemLoad = defined @NOP/nop-core.lua:143
SetEnabledState = defined @ElvUI_Libraries/Core/Ace3/AceAddon-3.0/AceAddon-3.0.lua:420
GetLinesFromTooltipData = defined @NOP/nop-core.lua:112
T_ITEMS = {
}
OnEnable = defined @NOP/nop-core.lua:98
ButtonShow = defined @NOP/nop-button.lua:315
spellLoad = true
ButtonOnEnter = defined @NOP/nop-button.lua:135
frameHiderB = NOP_HiderB {
}
T_DISENCHANT_ITEMS = {
}
OnInitialize = defined @NOP/nop-core.lua:88
UnregisterAllEvents = defined @SharedMedia/libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:164
removekey = defined @NOP/nop-core.lua:359
itemLoad = true
ActionButton_HideOverlayGlow = defined @NOP/nop-button.lua:435
QUEST_ACCEPTED = defined @NOP/nop-events.lua:195
ItemGetSpell = defined @NOP/nop-item.lua:56
QBOnLeave = defined @NOP/nop-quest.lua:141
GetName = defined @ElvUI_Libraries/Core/Ace3/AceAddon-3.0/AceAddon-3.0.lua:275
ActionButton_GetOverlayGlow = defined @NOP/nop-button.lua:413
QBSkin = defined @NOP/nop-quest.lua:264
ButtonLoad = defined @NOP/nop-button.lua:256
ButtonReset = defined @NOP/nop-button.lua:191
PLAYER_LEVEL_UP = defined @NOP/nop-events.lua:189
Print = defined @ElvUI_Libraries/Core/Ace3/AceConsole-3.0/AceConsole-3.0.lua:50
GetReputation = defined @NOP/nop-core.lua:506
GET_ITEM_INFO_RECEIVED = defined @NOP/nop-events.lua:220
ItemIsUnusable = defined @NOP/nop-item.lua:250
QBKeyBind = defined @NOP/nop-quest.lua:168
Profile = defined @NOP/nop-core.lua:335
ACTIONBAR_UPDATE_COOLDOWN = defined @NOP/nop-events.lua:202
UnregisterEvent = defined @SharedMedia/libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:143
SetDef

Thank you.
Please try the next alpha version, which should be available in the next minutes/hour.

Downloaded alpha v1.6-2-g5ffabcc and got the followeing error:

3x NOP/nop-item.lua:105: bad argument #1 to 'match' (string expected, got table)
[string "=[C]"]: in function `match'
[string "@NOP/nop-item.lua"]:105: in function `ItemGetLockPattern'
[string "@NOP/nop-item.lua"]:127: in function `ItemGetPattern'
[string "@NOP/nop-item.lua"]:229: in function `ItemScan'
[string "@NOP/nop-item.lua"]:409: in function `?'
[string "@ElvUI_Libraries/Core/Ace3/AceTimer-3.0-17/AceTimer-3.0.lua"]:55: in function <...UI_Libraries/Core/Ace3/AceTimer-3.0/AceTimer-3.0.lua:50>

Locals:
(*temporary) = <table> {
 leftColor = <table> {
 }
 type = 0
 leftText = "Requires Lockpicking (30)"
 args = <table> {
 }
}
(*temporary) = "%d+"
(*temporary) = "string expected, got table"

Thanks. Can you try with the next alpha as well please?
Made a bad paste mistake there :)

Tested version NOP-v1.6a-1-gb192f0c, worked perfectly

Thank you for verifying!