edit: okay so the following is still happening... but villagers with beds in two block high ceilings suffocating... this has started to happen again too... alot. im pretty sure it was fixed in 1.11.2... added a pic. its clearly resurfaced in 1.11.4 somehow.

villagers disappear for no apparent reason and it can happen when i just look away...

for example, i was watching my auto farm cycle. the villager then started planting. so i turned around to check the timers... i was less than 50 blocks away for only a few seconds. when i go back to check on him, hes gone... didnt even finish planting.

that was in a flat world with mob spawn turned off... it had been happening before, but i didnt realise they were literaly poofing as soon as i turned my back. the only reason i immediately noticed this time was because he was the only mob in the whole world...

edit: still happening as of 1.11.4 and its still confounding. really wish i had some more to add : /

adding a pic of the 12 man golem farm i was running. even had a escapee catcher and farm land to compensate for the despawning... geuss it couldnt keep up.