I'm not sure if it's related to this, but I can't get spell traces to work for shaman, the precreated traces nor custom created traces. Doesn't work if I use SoD or normal spells (such as Lesser Healing Wave id 8004) They seem to work fine on priest, even for SoD Spells (although there are retail equivilents). Unsure if this is SoD exclusive error.

1x Aptechka/Aptechka.lua:3747: attempt to index field 'assignto' (a nil value)
[string "@Aptechka/Aptechka.lua"]:3747: in function ListSpellsForWidget' [string "@Aptechka/Options/WidgetForms.lua"]:189: in function <Aptechka/Options/WidgetForms.lua:187> [string "=[C]"]: ? [string "@Altoholic/libs/AceGUI-3.0-41/AceGUI-3.0.lua"]:66: in function <...faceAltoholic/libs/AceGUI-3.0/AceGUI-3.0.lua:64> [string "@Altoholic/libs/AceGUI-3.0-41/AceGUI-3.0.lua"]:300: in function Fire'
[string "@Altoholic/libs/AceGUI-3.0-41/widgets/AceGUIWidget-Button.lua"]:26: in function <...olic/libs/AceGUI-3.0/widgets/AceGUIWidget-Button.lua:25>

Locals:
self = Aptechka {
0 =
UNIT_MAXPOWER = defined @Aptechka/Aptechka.lua:1474
loadedAuras =

{
}
UNIT_AFK_CHANGED = defined @Aptechka/Aptechka.lua:1407
ForEachFrame = defined @Aptechka/Aptechka.lua:1918
FrameColorize = defined @Aptechka/Aptechka.lua:2002
UNIT_MAXHEALTH = defined @Aptechka/Aptechka.lua:1114
FrameStartTrace = defined @Aptechka/Aptechka.lua:1264
ScanAuras = defined @Aptechka/Aptechka.lua:3463
IsGroupEnabled = defined @Aptechka/Aptechka.lua:2336
FrameUpdateIncomingCast = defined @Aptechka/Aptechka.lua:4208
FrameUpdateStagger = defined @Aptechka/Aptechka.lua:1702
RepositionAnchors = defined @Aptechka/Aptechka.lua:2512
RAID_TARGET_UPDATE = defined @Aptechka/Aptechka.lua:1913
FrameReadyCheckFinished = defined @Aptechka/Aptechka.lua:1985
NormalizeWidgetContent = defined @Aptechka/frame.lua:627
Reconfigure = defined @Aptechka/Aptechka.lua:910
UNIT_HEAL_PREDICTION = defined @Aptechka/Aptechka.lua:426
PLAYER_LOGIN = defined @Aptechka/Aptechka.lua:299
FixWidgetsAfterUpgrade = defined @Aptechka/frame.lua:93
UNIT_SPELLCAST_SENT = defined @Aptechka/Aptechka.lua:1672
UNIT_SPELLCAST_DELAYED = defined @Aptechka/Aptechka.lua:4298
PLAYER_FOCUS_CHANGED = defined @Aptechka/Aptechka.lua:1958
Lock = defined @Aptechka/Aptechka.lua:3730
db = {
}
ReconfigureTestHeaders = defined @Aptechka/frame.lua:3889
CreateCoordStatusBar = defined @Aptechka/frame.lua:3745
SafeCall = defined @Aptechka/Aptechka.lua:2619
EffectListPostUpdate = defined @Aptechka/Aptechka.lua:3355
GenerateMergedConfig = defined @Aptechka/Aptechka.lua:709
ShakeUnitButtons = defined @Aptechka/Aptechka.lua:2146
TestDebuffSlotsForUnit = defined @Aptechka/Aptechka.lua:3564
ToggleCompactRaidFrames = defined @Aptechka/Aptechka.lua:826
FrameUpdateUnitColor = defined @Aptechka/Aptechka.lua:929
DispelTypeProc = defined @Aptechka/Aptechka.lua:3399
UpdateWidget = defined @Aptechka/Aptechka.lua:2895
FrameCheckPhase = defined @Aptechka/Aptechka.lua:1218
TestCastBars = defined @Aptechka/Aptechka.lua:3611
UNIT_ENTERED_VEHICLE = defined @Aptechka/Aptechka.lua:1584
INCOMING_RESURRECT_CHANGED = defined @Aptechka/Aptechka.lua:1213
FrameUpdateRaidTarget = defined @Aptechka/Aptechka.lua:1905
GetCurrentGroupType = defined @Aptechka/Aptechka.lua:1840
ReconfigureProtected = defined @Aptechka/Aptechka.lua:982
UpdateAbsorbBarConfig = defined @Aptechka/Aptechka.lua:1065
FrameReadyCheckConfirm = defined @Aptechka/Aptechka.lua:1970
FrameUpdateName = defined @Aptechka/Aptechka.lua:862
PrintDeadAssignmentWarning = defined @Aptechka/Aptechka.lua:2813
UNIT_HEAL_ABSORB_AMOUNT_CHANGED = defined @Aptechka/Aptechka.lua:1102
ToggleUnlock = defined @Aptechka/Aptechka.lua:3722
UNIT_THREAT_SITUATION_UPDATE = defined @Aptechka/Aptechka.lua:1668

Hmm, are you sure you have those spells assigned somewhere? That error is very benign and only affects GUI, nothing to do with traces not working.
Otherwise, traces should work fine as long as spell ID is correct, and each rank has its own spell ID btw, in case you added something.

Post me your config from WTF/.../SavedVariables/Aptechka.lua if you won't fix it

I stripped out my character names if that's ok, but here it is.
I tried 399954 because the others weren't working.

	["DB_VERSION"] = 15,
	["global"] = {
		["customDebuffHighlights"] = {
			["Custom"] = {
				[23230] = {
					23230, -- [1]
					3, -- [2]
					"Warrior Blood Fury debuff", -- [3]
				},
			},
		},
		["customBlacklist"] = {
			[26218] = true,
		},
	},
	["profiles"] = {
		["Default"] = {
			["y"] = -198.0948944091797,
			["x"] = -407.3653259277344,
			["showCCList"] = true,
			["petGroup"] = true,
			["clampIncomingHeal"] = false,
			["showTargetedCount"] = true,
		},
		["Shaman"] = {
			["y"] = -198.0948944091797,
			["x"] = -407.3653259277344,
			["showTargetedCount"] = true,
			["petGroup"] = true,
		},
	},
}
AptechkaConfigCustom = {
	["HUNTER"] = {
	},
	["WARRIOR"] = {
	},
	["WARLOCK"] = {
	},
	["SHAMAN"] = {
		["traces"] = {
			[415240] = {
				["clones"] = false,
				["template"] = "HealTrace",
				["isAdded"] = true,
				["id"] = 415240,
				["name"] = "Healing RainTrace",
			},
			[399954] = {
				["name"] = "Chest Rune AbilityTrace",
				["isAdded"] = true,
				["id"] = 399954,
				["assignto"] = {
					["spell1"] = true,
				},
				["fade"] = 0.7,
			},
			[8004] = {
				["id"] = 8004,
				["template"] = "HealTrace",
				["name"] = "Lesser Healing WaveTrace",
				["isAdded"] = true,
			},
		},
		["auras"] = {
			[415240] = {
				["isAdded"] = true,
				["id"] = 415240,
				["text"] = "R",
				["assignto"] = {
					["icon"] = false,
					["spell1"] = false,
					["border"] = true,
					["totemCluster1"] = false,
				},
				["infoType"] = "DURATION",
				["isMine"] = true,
				["name"] = "Healing Rain",
				["realID"] = 415240,
				["priority"] = 75,
				["color"] = {
					0.7647059559822083, -- [1]
					1, -- [2]
					0.5215686559677124, -- [3]
					1, -- [4]
				},
			},
		},
	},
	["MAGE"] = {
	},
	["DRUID"] = {
	},
	["GLOBAL"] = {
		["auras"] = {
			[401859] = {
				["clones"] = {
					[401880] = true,
					[401882] = true,
					[401877] = true,
					[402832] = true,
					[401863] = true,
				},
				["global"] = true,
				["isAdded"] = true,
				["color"] = {
					1, -- [1]
					0, -- [2]
					0.5254902243614197, -- [3]
					1, -- [4]
				},
				["isMine"] = false,
				["infoType"] = "COUNT",
				["name"] = "Prayer of Mending",
				["maxCount"] = 5,
				["assignto"] = {
					["spell1"] = false,
					["bar4text"] = true,
					["bar4"] = true,
				},
				["realID"] = 401859,
				["id"] = 401859,
				["foreigncolor"] = {
					1, -- [1]
					0.05882353335618973, -- [2]
					0.5372549295425415, -- [3]
				},
			},
		},
	},
	["PRIEST"] = {
	},
}

Alright, I didn't find anything wrong there, just wrong spell IDs.
But I separated Lesser Healing Wave from Healing Wave in the config, maybe that was the issue somehow.
And I added /apt debug command in the update to look for the correct spell IDs.
Just look for the one with SPELL_HEAL event or SPELL_PRERIODIC_HEAL for Healing Rain.

But I separated Lesser Healing Wave from Healing Wave in the config, maybe that was the issue somehow.
This fixed the LHW issue.

And I added /apt debug command in the update to look for the correct spell IDs.
Just look for the one with SPELL_HEAL event or SPELL_PRERIODIC_HEAL for Healing Rain.

This helped, and I got it working for healing rain, I noticed that the changes don't actually take effect until a /reload though. Not sure if that's intentional or bug.

Healing Stream Totem still doesn't work. I'm guessing because it's not actually cast by the player, but instead cast by the totem. It's not a huge deal, just thought it'd be fun to test.

ID: 5672 Healing Stream SPELL_PERIODIC_HEAL 8465 Creature-0-5163-1-18526-3527-000013B969 ==> Creature-0-5163-1-18526-3527-000013B969 8465 6