When loading into a data-model (aka, Roblox local save file or public file or any file, including team-create)
It runs the physics for a few seconds, causing all unanchored parts in the data-model to fall and save.
These changes are visible to everyone, including when publishing the game.
This issue seems to only happen for me, and not others.
Here are my enabled beta features:
Trying this with just the Beta features you identified enabled, I am unable to reproduce. Have you tried disabling any of the plugins to see if the problem persists? Based on your screenshot, several look like they have been updated in the last few weeks and we have introduced enhancements to physics control that they might have started using ( this feature for example New StepPhysics Plugin API ).
settings().Physics.PhysicsEnvironmentalThrottle = game:GetService("RunService"):IsRunning()
and Enum.EnviromentalPhysicsThrottle.Disabled
or Enum.EnviromentalPhysicsThrottle.DefaultAuto