This issue manifested for me when using tranquility. I ended up finding two issues
Typo in Cursor:OnEvent Castbar instead of CastBar
It looks like the arguments to UnitChannelInfo have changed (8.0.1 (2018-07-17): Removed the second parameter, "nameSubtext". Second parameter is now "text" (former third parameter)) Which meant that endTime actually ended up being the bool isTradeSkill.
This issue manifested for me when using tranquility. I ended up finding two issues