Here's a temporary fix you can use while waiting for an update:
Change line 899 of TipTac\Core.lua to:
local isUnit = UnitExists("mouseover") or (mouseFocus and mouseFocus.GetAttribute and mouseFocus:GetAttribute("unit")); -- Az: GetAttribute("unit") here is bad, as that will find things like buff frames too
Change line 1005 of Core.lua to:
unit = mFocus and mFocus.GetAttribute and mFocus:GetAttribute("unit");
Removed pointless "~= nil"