Ever since a recent build (I would say 2 months ago), avatar got reset once the player stay still for a while (say 10~30 minutes) and then start to move again (i.e. moving their head or hand, does not necessarily mean moving by the thumb stick).
By being reset, I mean non-saved parameters are reset, and animation controllers are loaded into Default states. It is somehow similar to when switching safety level, except for it is only for the player themself.
This is especially annoying because people sleep with their feet anchored, but when they move a bit, their avatar got reset and their feet got anchored to the same position of their head.