This one is kind of weird. My horde DK works fine, but my Alliance DK's scourge strike and festering strike doesn't show up. Error below:
2309x HeroRotation_DeathKnight\Unholy.lua:324: attempt to index global 'ArmyoftheDead' (a nil value)
[string "@HeroRotation_DeathKnight\Unholy.lua"]:324: in function <HeroRotation_DeathKnight\Unholy.lua:297>
[string "@HeroRotation_DeathKnight\Unholy.lua"]:438: in function `?'
[string "@HeroRotation\Main.lua"]:445: in function <HeroRotation\Main.lua:423>

Locals:
(*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = true
(*temporary) = 276837
(*temporary) = "attempt to index global 'ArmyoftheDead' (a nil value)"
HR =

{
CastPooling = defined @HeroRotation\Core.lua:170
MaxQueuedCasts = 3
CmdHandler = defined @HeroRotation\Core.lua:264
PulseInit = defined @HeroRotation\Main.lua:355
GetTexture = defined @HeroRotation\Core.lua:46
APLInits = {
}
LastUnitCycledTime = 183389.240000
CastSuggested = defined @HeroRotation\Core.lua:241
CastQueuePooling = defined @HeroRotation\Core.lua:198
CastAnnotated = defined @HeroRotation\Core.lua:161
PulsePreInit = defined @HeroRotation\Main.lua:301
LeftIconFrame = HeroRotation_LeftIconFrame {
}
CastRightSuggested = defined @HeroRotation\Core.lua:252
GUISettings = {
}
LastUnitCycled = {
}
ChangePulseTimer = defined @HeroRotation\Main.lua:463
AoEON = defined @HeroRotation\Core.lua:349
NameplateIconFrame = HeroRotation_NameplateIconFrame {
}
CreateBackdrop = defined @HeroRotation\UI.lua:67
ToggleIconFrame = HeroRotation_ToggleIconFrame {
}
RightSuggestedIconFrame = HeroRotation_RightSuggestedIconFrame {
}
Commons = {
}
Print = defined @HeroRotation\Core.lua:31
ResetIcons = defined @HeroRotation\UI.lua:37
Cast = defined @HeroRotation\Core.lua:132
Pulse = defined @HeroRotation\Main.lua:423
Timer = {
}
MainFrame = HeroRotation_MainFrame {
}
Locked = defined @HeroRotation\Core.lua:360
Nameplate = {
}
CastLeftCommon = defined @HeroRotation\Core.lua:221
Ready = defined @HeroRotation\Main.lua:458
APLs = {
}
SuggestedIconFrame = HeroRotation_SuggestedIconFrame {
}
CastLeftOffset = 1
SmallIconFrame = HeroRotation_SmallIconFrame {
}
SetAPL = defined @HeroRotation\Core.lua:38
CastRightSuggestedOffset = 1
CastQueue = defined @HeroRotation\Core.lua:192
MainIconPartOverlayFrame = HeroRotation_MainIconPartOverlayFrame {
}
MainIconFrame = HeroRotation_MainIconFrame {
}
CastSuggestedOffset = 1
CastLeft = defined @HeroRotation\Core.lua:226
CastLeftNameplate = defined @HeroRotation\Core.lua:232
CastOffGCDOffset = 2
GUI = {
}
ON = defined @HeroRotation\Core.lua:355
CDsON = defined @HeroRotation\Core.lua:335
}
S = {
UnholyStrengthBuff = {
}
UnholyAssault = {
}
LightsJudgment = {
}
UnholyBlightDebuff = {
}
PoolResources = {
}
UnholyAssaultBuff = {
}
ArcanePulse = {
}
DeathCoil = {
}
ScourgeStrike = {
}
ArmyoftheDamned = {
}
ArmyoftheDead = {
}
FesteringStrike = {
}
Fireblood = {
}
DeathStrike = {
}
DeathStrikeBuff = {
}
ConvocationOfTheDead = {
}
DarkTransformation = {
}
SoulReaper = {
}
SacrificialPact = {
}
SummonGargoyle = {
}
DeathAndDecay = {
}
UnholyPact = {
}
Epidemic = {
}
RaiseDead = {
}
ClawingShadows = {
}
Defile = {
}
DeathsDue = {
}
DeathAndDecayBuff = {
}
SuddenDoomBuff = {
}
UnholyBlight = {
}
MindFreeze = {
}
Pestilence = {
}
AncestralCall = {
}
BagofTricks = {
}
BloodFury = {
}
ArcaneTorrent = {
}
VirulentPlagueDebuff = {
}
FesteringWoundDebuff = <t

Can confirm, my dark iron dwarf is having the same error. Keeps saying armyofthedead a nil value, same error you are getting. But It is very rare. It does not have to do with Army being on CD or off as I have the error both ways. I am wondering if my dark iron racial is what is causing this issue as I notice it mainly after it tells me to do dark transformation and I have that macrod for Fireblood too.

Message: Interface\AddOns\HeroRotation_DeathKnight\Unholy.lua:324: attempt to index global 'ArmyoftheDead' (a nil value)
Time: Sat Jan 23 10:07:19 2021
Count: 161
Stack: Interface\AddOns\HeroRotation_DeathKnight\Unholy.lua:324: attempt to index global 'ArmyoftheDead' (a nil value)
[string "@interface\AddOns\HeroRotation_DeathKnight\Unholy.lua"]:324: in function <Interface\AddOns\HeroRotation_DeathKnight\Unholy.lua:297>
[string "@interface\AddOns\HeroRotation_DeathKnight\Unholy.lua"]:438: in function `?'
[string "@interface\AddOns\HeroRotation\Main.lua"]:445: in function <Interface\AddOns\HeroRotation\Main.lua:423>

Locals: (*temporary) = nil
(*temporary) = nil
(*temporary) = nil
(*temporary) = true
(*temporary) = 276837
(*temporary) = "attempt to index global 'ArmyoftheDead' (a nil value)"
HR =

{
CastPooling = defined @interface\AddOns\HeroRotation\Core.lua:170
MaxQueuedCasts = 3
CmdHandler = defined @interface\AddOns\HeroRotation\Core.lua:264
PulseInit = defined @interface\AddOns\HeroRotation\Main.lua:355
GetTexture = defined @interface\AddOns\HeroRotation\Core.lua:46
APLInits = {
}
LastUnitCycledTime = 526095.082000
CastSuggested = defined @interface\AddOns\HeroRotation\Core.lua:241
CastQueuePooling = defined @interface\AddOns\HeroRotation\Core.lua:198
CastAnnotated = defined @interface\AddOns\HeroRotation\Core.lua:161
PulsePreInit = defined @interface\AddOns\HeroRotation\Main.lua:301
LeftIconFrame = HeroRotation_LeftIconFrame {
}
CastRightSuggested = defined @interface\AddOns\HeroRotation\Core.lua:252
GUISettings = {
}
LastUnitCycled = {
}
ChangePulseTimer = defined @interface\AddOns\HeroRotation\Main.lua:463
AoEON = defined @interface\AddOns\HeroRotation\Core.lua:349
NameplateIconFrame = HeroRotation_NameplateIconFrame {
}
CreateBackdrop = defined @interface\AddOns\HeroRotation\UI.lua:67
ToggleIconFrame = HeroRotation_ToggleIconFrame {
}
RightSuggestedIconFrame = HeroRotation_RightSuggestedIconFrame {
}
Commons = {
}
Print = defined @interface\AddOns\HeroRotation\Core.lua:31
ResetIcons = defined @interface\AddOns\HeroRotation\UI.lua:37
Cast = defined @interface\AddOns\HeroRotation\Core.lua:132
Pulse = defined @interface\AddOns\HeroRotation\Main.lua:423
Timer = {
}
MainFrame = HeroRotation_MainFrame {
}
Locked = defined @interface\AddOns\HeroRotation\Core.lua:360
Nameplate = {
}
CastLeftCommon = defined @interface\AddOns\HeroRotation\Core.lua:221
Ready = defined @interface\AddOns\HeroRotation\Main.lua:458
APLs = {
}
SuggestedIconFrame = HeroRotation_SuggestedIconFrame {
}
CastLeftOffset = 1
SmallIconFrame = HeroRotation_SmallIconFrame {
}
SetAPL = defined @interface\AddOns\HeroRotation\Core.lua:38
CastRightSuggestedOffset = 1
CastQueue = defined @interface\AddOns\HeroRotation\Core.lua:192
MainIconPartOverlayFrame = HeroRotation_MainIconPartOverlayFrame {
}
MainIconFrame = HeroRotation_MainIconFrame {
}
CastSuggestedOffset = 1
CastLeft = defined @interface\AddOns\HeroRotation\Core.lua:226
CastLeftNameplate = defined @interface\AddOns\HeroRotation\Core.lua:232
CastOffGCDOffset = 1
GUI = {
}
ON = defined @interface\AddOns\HeroRotation\Core.lua:355
CDsON = defined @interface\AddOns\HeroRotation\Core.lua:335
}
S = {
UnholyStrengthBuff = {
}
UnholyAssault = {
}
LightsJudgment = {
}
UnholyBlightDebuff = {
}
PoolResources = {
}
UnholyAssaultBuff = {
}
ArcanePulse = {
}
DeathCoil = {
}
ScourgeStrike = {
}
ArmyoftheDamned = {
}
ArmyoftheDead = {
}
FesteringStrike = {
}
Fireblood = {
}
DeathStr