Recently started getting this many times a night when playing RBGs. (Retail WoW)
unfortunately wont be able to test without addons at this stage, but perhaps something obvious with this

51x OmniBar\OmniBar-v12.1.lua:734: attempt to call upvalue 'IsRatedBattleground' (a nil value)

getting the same error in every rated BG after last update

Thanks!