Withers are now able to have potions other than Instant Health and Instant Damage applied to them, as well as the Glowing effect from a Spectral Arrow.
MC-226948
Withers are now affected by potion effects
Resolved
Fixed
8
chumbanotz
mgatland
Confirmed
Important
Mob behaviour
affect, glowing, potion_effect, wither
1.17 Pre-release 2, 1.17 Pre-release 3, 1.17 Pre-release 4, 1.17 Pre-release 5, 1.17 Release Candidate 1, 1.17 Release Candidate 2, 1.17
1.17.1 Pre-release 1
Retrieved
I can confirm that this is an issue. Just for clarification reasons, this did not happen in 1.16.5.