Physics parts attached to anchored part by ropes during tween not updating until tween has finished

I have a crane model that I was trying to make when I came across this issue, and you can see my initial post on the Scripting Support section here.
Here’s a video showing the problem:

When I begin tweening the anchored part’s CFrame, the attached part freezes and does not unfreeze until the tween has finished. If the network ownership of the unanchored part is manually assigned to a user (or the user approaches the part and network ownership is automatically handed over), only that user sees the part moving. The server, as well as all other clients, view it as being stuck until network ownership is changed again or the part’s tween finishes.
Here’s the place file from the video: Baseplate.rbxl (22.4 KB)


Thanks for reporting this! We are investigating.


Hi, we are still working on fixing this bug, however there’s another workaround you can try:

You can use TweenService to move the Rope’s attachment rather than the anchored part, and replication should work correctly.


Hey! I’ve encountered the same issue which I PMed to some of the DevRel team to move into this section since I didn’t have permissions to create a new thread (not a Regular), but I seem to be able to reply here.

I’ve made a repro for this:

Reproduction steps:

  1. Open the rbxl reproduction file
  2. Press play (not Run)
  3. Under Workspace.Model.Script, there is a EnableBug BoolValue - toggle it on to showcase the issue.
  4. Whenever EnableBug is on, the client should be unable to see any replication changes from AlignPosition - if you switch the mode from client to server, you will notice that the model is being moved on server, but not on client.

Reproduction file:
AlignPosition-Attachment_Repro.rbxl (25.3 KB)

@The_Sink the only workaround for this I found was to manually update the Attachment’s WorldPosition or Position properties (pretty much what @kleptonaut kleptonaut said) rather than the BasePart it is parented under :slightly_smiling_face:


Tweening the WorldPosition of the attachments seems to work great as a temporary solution, thank you!


Is this fixed yet? It’s been a while since this topic was updated.

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Hello, everyone! Does this issue occur anymore for any of you?


I have tested the place file and it’s still occuring

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I haven’t encountered any problems personally (due to the workaround), but the original repro place file still shows the issue happening.

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Sorry for bumping up this topic but yes, this bug is still present today.

A quick repro demo, Instead of ropes, I am using HingeConstraint.
It appears that it only replicates for the network ownership of the unanchored parts, which means if a player owns the network ownership of the parts, they will only perform in the expected behavior on the client’s screen but not on the server.

(Press F8 for expected behavior, F5 for the bugged behavior)
HingeReplicationBug_Repro.rbxl (35.0 KB)