For the last few versions of the game and the SDK (confirmed to still exist as of SDK version 3.8.2, and game build 1664), the VRC Position and Parent Constraints behave strangely when toggling the "Freeze To World" setting with animations.

When toggling the setting on, there is no abnormal behaviour, but when toggling the setting off again, the constraint's position is set to double the distance moved since the setting was last enabled, before correcting itself almost immediately, and moving to the source element it is constrained to. This is not too much of an issue for the local user, but if the incorrect movement of the constraint is moved outside of the field of view of a remote player, its position will not be corrected until they look at the position it was incorrectly moved to first.

To give a specific example, since the issue is somewhat hard to describe, the core of my issue is that the entire mesh of my avatar is dependent on the position of a VRC Position Constraint. Say that I begin at the world origin, with "Freeze To World" enabled, and I walk 10m away from the world origin. When I disable the "Freeze To World" setting, my avatar will briefly appear as though it teleports 10m away from me in the same direction I had just moved (and therefore 20m from the world origin), before almost instantly teleporting back to my actual position (where the source element it is constrained to is located). However, if a remote player is looking at me, facing the world origin (and therefore facing away from where it is incorrectly displaced to), they will report that my avatar has disappeared. The avatar will stay invisible to them until they look at where the constraint was incorrectly displaced to, at which point they will report that my avatar is back where it should be.

I assume this issue is caused by the position of constraints not being updated when they are not in view, but I have found no workaround to this issue which prevents the incorrect displacement.

Thank you for your time, and let me know if you need any more information!