For example, I saw about two wolves, and I went to go get some bones. When I came back, they weren't there, I looked all around for them, but they just Disappeared.
A lot of monsters will spawn, then de-spawn. They just disappear into thin air.
Linked issues
is duplicated by 12
MCPE-96671
Animals despawn to quickly
Resolved
MCPE-121799
Mobs naturally spawned despawn after losing range then going and ganging range again.
Resolved
MCPE-130410
Goat despawns in boat
Resolved
MCPE-133586
Mobs in boat despawning on realm
Resolved
MCPE-152287
The Mobs that killed me disappear
Resolved
7 more links
This is the new despawning mechanics added in 1.16. More information on how the despawning mechanics work can be found in the 1.16.0 changelog.