Character replication inconsistent/spazzing when client jumps from falling object

I am experiencing a bug which causes replication of a player’s character to spaz out when they jump off of a falling object. This bug has existed in my game for few months (this is just when I started noticing it after I added a new mechanic, so it easily could have existed for much longer) but I didn’t look into it until recently. I just assumed it was a script in my game causing it, but it turns out it can be reproduced easily in any game that has this type of mechanic. Here’s a video below showing how to reproduce. In this case, I’m just using a completely empty baseplate so I don’t think a repro file is necessary:

I’ve also tested this in jailbreak with their helicopters and the bug happens there as well. As you can see, the position of the player on the client (left window) is correct, but on the server (right window) it is extremely inconsistent and teleporting around. This happens in game as well and replicates to all other players. The severity of the bug is somewhat inconsistent as well but seems to get more severe with a better jump. In the video, the bug is very clear in the first try but much less severe, however you can see that in the second try it is almost game-breaking.

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Hey TheHyb, thanks for your report! What you’re seeing is a result of how our interpolation system deals with humanoids on unowned platforms. We have a special case in interpolation to keep the motion of the platform consistent from the POV of the client controlling the humanoid. In your video as the platform falls through the air and hits the ground, the humanoid is still “bound” to that platform (meaning that the interpolation of the humanoid is happening w.r.t. the position and velocity of the platform), so the platform bouncing causes the humanoid’s position to look a bit crazy. We don’t immediately separate the humanoid and the platform in our interpolation system because we want to allow players to run and jump on platforms. I’ve made a ticket in our internal tracking system for this, we will see if there is a way to mitigate it.

If you’re interested in learning more here’s the original release post for the humanoids on platforms system: Characters on Moving Platforms - Now Live

Edit: Fixed my description of the issue!

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Hey GroupyClumpy, I’m following up because this issue still exists. Any ETA on a fix?

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Unfortunately this issue is still in our backlog, I will post any updates I have in the future here.

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