The combat routine does not appear to support the channeling of spells (e.g. wither cannot be used with cast while channeling to support spirit offering and desecrate). Can this issue please be fixed? Thank you.
You need your own custom routine to handle advanced logic correctly with Wither now. The logic in OldRoutine was before it was made a channeling skill, so it doesn't fully cast anymore.
If you just want it to be spam cast like other skills, here's OldRoutine with the old Wither logic removed so the slots configuration works again: OldRoutine.cs * GitHub
I'll include that in the next version since the channeled Wither casting logic won't work with what's there, but for anything better, you need your own logic/routine that handles that skill and the conditions you want to cast or stop using it on as OldRoutine is primarily for skills you spam cast that does damage.