Classic Era throws this bug.

12x Details_Vanguard\Details_Vanguard.lua:3: attempt to call field 'IsWotLKWow' (a nil value)
[string "@Details_Vanguard\Details_Vanguard.lua"]:3: in main chunk

Locals:
(*temporary) = nil
(*temporary) = "attempt to call field 'IsWotLKWow' (a nil value)"

12x ...rfaceDetails_RaidCheck\Details_RaidCheck.lua:3: attempt to call field 'IsWotLKWow' (a nil value)
[string "@Details_RaidCheck\Details_RaidCheck.lua"]:3: in main chunk

Locals:
(*temporary) = nil
(*temporary) = "attempt to call field 'IsWotLKWow' (a nil value)"

Also this one. I think it's the same.