Joints in Unanchored Assembly Spazzing/Shaking

Put quite simply, modifying Joints in any unanchored assembly on replication to the Server from the Client causes severe shaking of that assembly to every other Client. Server on test mode isn’t affected somehow. I’m doing something wrong…

1st Video

2nd Video

3rd Video (Client flying nominally?)

Final One (lol I'm crying rn)

I’ve seen this a few times and traded blows with the issue too many times.
How can I animate a Landing Gear or Player Head without this happening?

I’ve fined this down to Motor6Ds in a client network owned assembly causing stutter due to some crazy replication issues. Somehow, setting the smaller part involved to massless fixes this.

I found another issue where vehicles can have one of the attached parts in a hinge constraint fly about 25 studs in a random parallel direction under minor instability or external forces. Simply pausing the game engine in Studio (without any aerodynamic forces) and unpausing it causes this. The HingeConstraint’s do not return to their normal position, instead they just make the vehicle fly uncontrollably permanently.

I have had to fight all of these issues by checking every time to make sure it’s behaving and manually correcting the Physics Engine’s mistakes.

Please, does anybody have a solution or hints here? It’s getting kind of ridiculous, feeling really alone here :frowning: