The bug

When villagers sleep at night in a set of tiled beds, there seems to be a fairly high chance that any given villager will spontaneously stand up during the night. After they have stood up during a night cycle, I observed that they seemed to never slept in that bed again during subsequent nights. Instead, they stood on or near it throughout these later nights.

How to reproduce

I produced this result in both a flat world and a normal random map seed world. I placed a set of tiled beds in a 3x8 row, 24 beds in total, and surrounded the beds with a 2-high wall of glass around their perimeter. I then spawned 24 villagers into this bed chamber and set the game to night. This initial night time, all villagers successfully bonded to a bed within the glass chamber and slept in it. After 2 or 3 times cycling from night to day, by the 2nd or 3rd night, when I waited up to a few minutes during the night, I observed villagers standing up out of their bed. Setting the time to day and then night again, I observed the villagers that had stood up during the night never sleeping in their bed again, even after I tried setting it from day to night several more times.

I then tried some different things, like adding bells and/or workstations, cycling them through work times, etc. Bells seemed to give no improvement, but it seems like if they're bonded to a workstation around the perimeter of the bed chamber then their sleeping in the bed becomes more reliable. I wonder if their pathfinding around during different times of their workday makes them more able to get back into their bed?

Implications

May affect the mechanics of naturally-spawned villages. May affect iron farm designs.

Image

Please see the attached image, wherein I observe villagers who are permanently unable to sleep in the bed they initially bonded to in a prior night time.