The bug
When skeletons seek shelter from the sun, but there is no nearby shelter, they start drawing their bow to attack the player but stop and continue to walk away.
How to reproduce
Go to a flat area, for example a Void superflat world with a platform
Set the time to day
Spawn some skeletons
Switch to Survival or Adventure mode
Linked issues
Comments

Can reproduce on a void superflat world.

If they burn before seeing the player, they flee instead of targeting the player.

@@unknown, the issue described here was that they would fail to shoot the player if there was not shelter around (which has been fixed). If you think the behavior you are experiencing is a bug please create a new report (after searching for existing ones).
Is this still an issue in 19w13a?