Affects Version/s: 18.104.22.168 Beta, 22.214.171.124 Beta, 126.96.36.199 Beta
Fix Version/s: None
Spawning wither skeletons under a tree in the overworld will not leave the area, unlike most undead mobs that can burn in the daylight (besides wither bosses, husks and zombie pigmen), wither skeletons don't not burn, but they still need a shaded area even though they don't burn in the daylight.
1. Spawn wither skeleton under a tree
2. Go to survival
3. The wither skeleton will stay in the shaded area (tree) and never wanders away.
Wither skeletons don't chase players when they are under a tree as they think they can burn.
The wither skeletons should always be chasing the player and not think that they can burn.