Wither Skeletons don't attempt to hide from sunlight, but once they get under an overhang, they don't move out from under it, not even to attack a player.
Noticed in this video (at about 29 minutes in): https://www.youtube.com/watch?v=HMs0eIayCKE
It was recorded in 1.8-pre1.
Tested further by myself in 1.8-pre2. They came out from under the overhang a few times, but most of the time they didn't. They came out about 18% of the time (7 times out of 40 tries).
I will upload a screenshot of my testing apparatus if requested.
Relates to MC-8671, which is fixed.
Linked issues
Comments
Sonicwave
@ Sonicwave:
They do not attempt to hide from sunlight anymore. That's why I said that issue is fixed even though it's marked as "Works and Intended" (it was fixed sometime after that issue was resolved).
Since they don't hide from the sun anymore, it's inconsistent that they won't leave an overhang most of the time, hence why I created this report.
Sonicwave
Confirmed for 1.8.
kumasasa
Is this still an issue in the current Minecraft Snapshot 15w47c or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.
Since they share the same Mob ID as regular skeletons, I believe that they still attempt to hide from sunlight, and therefore don't come out into it. (BTW the issue that you referenced was resolved with "Works As Intended" not "Fixed".)
http://minecraft.gamepedia.com/Wither_Skeleton#Trivia