Hope I'm not barking up the wrong tree here because I haven't seen it myself (but by definition you wouldn't see this bug). I was reading up on how witches generate and I noticed that when world generation creates a witch hut it also creates a witch. Since this is outside of the 128 block range wouldn't she always despawn? You'd have to turn your view distance to about 6 chunks or less to avoid this (8 chunks would be exactly 128 blocks, but only if the hut is perfectly lined up with you on the x or z axis). So did Mojang overlook this flaw or did they think their way around it? (setting persistence would fix it, as would making the 128 block despawn rule not apply to the witch)
Sorry if there's already been a workaround to this and I'm wasting your time. I don't know for sure that it's a problem, it just seems like it would be and I've found no info anywhere that says anyone but me has thought of this flaw.