This has been happening for at least a month of longer, with some unfortunate losses. But here is the most up-to-date knowledge I can provide. Note this is approximate and second hand as my friends have experienced this most recently on my Realm:
Named, max traded villager, for context that disappeared.
what you were doing leading up to the mobs disappearing
Building a new structure near my house/spawn point (changed via bed)
single vs. multiplayer, local vs server/realm
Multiplayer, Realm
how far you traveled
I was moving within a 3-5 chunk radius around my spawn point, but the distance between my spawn point and where the building the villager was in is 1511.589891
how long the current or previous play session lasted
Unknown, was playing and connected for at least an hour or more
whether the despawns were near a player spawn point or if you had changed your player spawn point during the session,
Near my spawn point, no changes
if you experienced lag or anything else abnormal.
Nothing during this play session
Separate instance, but within the same area.
what you were doing leading up to the mobs disappearing
Standing within 50 - 100 blocks away from the villager. I watched it travel down a single block near an azalea tree, and then just vanish
single vs. multiplayer, local vs server/realm
Multiplayer, Realm
how far you traveled
Maybe 5-10 blocks? Was walking into the building the villager was supposed to be in, but it got out
how long the current or previous play session lasted
Had been connected and playing for at least 5 minutes
whether the despawns were near a player spawn point or if you had changed your player spawn point during the session,
Within 1500 blocks of my spawn bed
if you experienced lag or anything else abnormal.
Nothing during this play session
Note: This is on a 1.17 Realm with the Caves and Cliffs Experimental Flag enabled.
Hunter Skrasek
This has been happening for at least a month of longer, with some unfortunate losses. But here is the most up-to-date knowledge I can provide. Note this is approximate and second hand as my friends have experienced this most recently on my Realm:
Named, max traded villager, for context that disappeared.
what you were doing leading up to the mobs disappearing
Building a new structure near my house/spawn point (changed via bed)
single vs. multiplayer, local vs server/realm
Multiplayer, Realm
how far you traveled
I was moving within a 3-5 chunk radius around my spawn point, but the distance between my spawn point and where the building the villager was in is 1511.589891
how long the current or previous play session lasted
Unknown, was playing and connected for at least an hour or more
whether the despawns were near a player spawn point or if you had changed your player spawn point during the session,
Near my spawn point, no changes
if you experienced lag or anything else abnormal.
Nothing during this play session
Separate instance, but within the same area.
what you were doing leading up to the mobs disappearing
Standing within 50 - 100 blocks away from the villager. I watched it travel down a single block near an azalea tree, and then just vanish
single vs. multiplayer, local vs server/realm
Multiplayer, Realm
how far you traveled
Maybe 5-10 blocks? Was walking into the building the villager was supposed to be in, but it got out
how long the current or previous play session lasted
Had been connected and playing for at least 5 minutes
whether the despawns were near a player spawn point or if you had changed your player spawn point during the session,
Within 1500 blocks of my spawn bed
if you experienced lag or anything else abnormal.
Nothing during this play session
Note: This is on a 1.17 Realm with the Caves and Cliffs Experimental Flag enabled.