Would get a LUA error in Cast.lua on line 356 because of trying to do a mathematical operation on a Boolean value. UnitChannelInfo changed for patch 8.0.1 to fewer parameters, so updating line 355 from:
_, _, _, _, castStartTime, castEndTime = UnitChannelInfo(unit)
to:
_, _, _, castStartTime, castEndTime = UnitChannelInfo(unit)
corrected the issue for me.
Updated based on API info from https://wow.gamepedia.com/API_UnitChannelInfo

Fixed in next release