Getting this BugSack dump when attempting to use an ability that's on an action bar slot I have hidden. Using abilities on the same action bar but on slots that aren't hidden works normally. Disabling Dominos and using the default UI bars with the bar hidden works normally. Reverting to version 10.2.14b resolves this issue.
Additionally, casted abilities such as flash of light are not triggering the global cooldown animation on the icon of the casted ability. It will display on other icons but not the one that was used.

40x FrameXML/MultiActionBars.lua:29: attempt to index local 'button' (a nil value)
[string "@FrameXML/MultiActionBars.lua"]:29: in function `MultiActionButtonUp'
[string "MULTIACTIONBAR2BUTTON8"]:4: in function <[string "MULTIACTIONBAR2BUTTON8"]:1>

Locals:
bar = "MultiBarBottomRight"
id = 8
bar = MultiBarBottomRight {
0 =
buttonPadding = 2
GetShowAllButtons = defined @FrameXML/ActionBar.lua:179
UpdateSystemSettingAlwaysShowButtons = defined @FrameXML/EditModeSystemTemplates.lua:994
UpdateMagnetismRegistration = defined @FrameXML/EditModeSystemTemplates.lua:731
GetSnapOffsets = defined @FrameXML/EditModeSystemTemplates.lua:609
UpdateFrameStrata = defined @FrameXML/ActionBar.lua:183
IsFrameAnchoredToMe = defined @FrameXML/EditModeSystemTemplates.lua:694
TrySetCompositeNumberSettingValue = defined @FrameXML/EditModeSystemTemplates.lua:212
downKeys =

{
}
GetFixedSize = defined @SharedXML/LayoutFrame.lua:156
buttonTemplate = "MultiBar2ButtonTemplate"
GetFixedWidth = defined @SharedXML/LayoutFrame.lua:148
useDefaultAnchors = false
GetSelectionOffset = defined @FrameXML/EditModeSystemTemplates.lua:540
ResetToDefaultPosition = defined @FrameXML/EditModeSystemTemplates.lua:254
oldGridSettings = {
}
GetScaledSelectionSides = defined @FrameXML/EditModeSystemTemplates.lua:532
SelectSystem = defined @FrameXML/EditModeSystemTemplates.lua:763
SetFixedWidth = defined @SharedXML/LayoutFrame.lua:135
GetFrameMagneticEligibility = defined @FrameXML/EditModeSystemTemplates.lua:714
AddLayoutChildren = defined @SharedXML/LayoutFrame.lua:55
IsBelowFrame = defined @FrameXML/EditModeSystemTemplates.lua:499
UpdateSystemSettingIconSize = defined @FrameXML/EditModeSystemTemplates.lua:933
SetFixedSize = defined @SharedXML/LayoutFrame.lua:143
HasActiveChanges = defined @FrameXML/EditModeSystemTemplates.lua:381
GetScaledCenter = defined @FrameXML/EditModeSystemTemplates.lua:525
DoesSettingDisplayValueEqual = defined @FrameXML/EditModeSystemTemplates.lua:445
UpdateDisplayInfoOptions = defined @FrameXML/EditModeSystemTemplates.lua:456
GetSystemName = defined @FrameXML/EditModeSystemTemplates.lua:822
ProcessMovementKey = defined @FrameXML/EditModeSystemTemplates.lua:39
GetSettingValueBool = defined @FrameXML/EditModeSystemTemplates.lua:436
HasCompositeNumberSetting = defined @FrameXML/EditModeSystemTemplates.lua:385
IsLayoutFrame = defined @SharedXML/LayoutFrame.lua:36
DoesSettingValueEqual = defined @FrameXML/EditModeSystemTemplates.lua:440
dividersDirty = false
MarkDirty = defined @SharedXML/LayoutFrame.lua:99
ShouldResetSettingsDialogAnchors = defined @FrameXML/EditModeSystemTemplates.lua:168
dirtySettings = {
}
UpdateGridLayout = defined @FrameXML/EditModeSystemTemplates.lua:870
IsToTheLeftOfFrame = defined @FrameXML/EditModeSystemTemplates.lua:481
GetSettingsDialogAnchor = defined @FrameXML/EditModeSystemTemplates.lua:465
hasActiveChanges = false
OnSystemLoad = defined @FrameXML/EditModeSystemTemplates.lua:3
ClearFrameSnap = defined @FrameXML/EditModeSystemTemplates.lua:653
GetCombinedCenterOffset = defined @FrameXML/EditModeSystemTemplates.lua:596
SetupSettingsDialogAnchor = defined @FrameXML/EditModeSystemTemplates.lua:369
IsShownOverride = defined @FrameXML/ActionBar.lua:282
dirty = false
SetPointBase = defined =[C]:-1
UpdateSystem = defined @FrameXML/EditModeSystemTemplates.lua:833
CacheGridSettings = defined @FrameXML/ActionBar.lua:65
UpdateDirtySettin

When reporting an issue, please try to reproduce the issue with just Dominos and Dominos_Config running.
Done

Addon Version
10.2.15-retail

World of Warcraft Version
Retail