Evokers aren't converting blue sheep into red sheep.
To reproduce, spawn a sheep, dye it blue, and then spawn an evoker. Nothing happens.
Linked issues
duplicates 1
Comments 4
Make sure your mobGriefing
gamerule is set to true.

Cannot reproduce either.
Oh yeah sorry mobgriefing was false.
Cannot reproduce. The evoker successfully converts the blue sheep to a red sheep.