Robotics drift occuring after self-docking when time warping or on save/load

[StormCircuit]

When robotics are used to dock a vehicle to its self it seems to trigger the old robotics drift bug:

This part is grabbed with a crappy recreation of the canadarm:

On timewarp/save/load/re-docking the part drifts:

To reproduce you should be able to dock a canadarm to its own craft, for example to dock to a station module like the ISS in real life, then undock the module thats been grabbed from the structure such that the arm is the only thing docked to it and finally re-dock the module elsewhere.

It is not entirely consistent in my experience, at least not visually, but doing this enough does over time consistently occur especially if you use a robotic arm a lot.

Save file and CKAN mod list within zip:
RoboticsDrift.zip

[gotmachine]

I didn't try with your save, but I didn't manage to reproduce what is shown in your screenshot.

I think it might be possible to get non-self docked docking ports that don't end up being aligned after they have been "promoted" from a self-docked to a regular docked state, although I didn't manage to reproduce it either.

But in any case this wouldn't result in what is shown in your screenshot, which is a misalignment between the docking ports and the part they are attached to.

For reference, these are the test crafts I used (only dependency is EasyRobotics) :
robotic crafts.zip

I probably need to test the save you provided...

Okay so I finally managed to load your save, but in it the docking ports are already misaligned and everything is undocked, so no very helpful...

[JonnyOThan]

I have been able to repro parts warping during timewarp in a self-attached state when robotics are applying a flex to them. And this seems likely correct.

I wonder if some piece of the puzzle is the reroot that likely happens when undocking a self-docked port. If the docking port is being deflected because of internal forces and then that gets snapshotted as the correct transform?

[gotmachine]

I have been able to repro parts warping during timewarp in a self-attached state when robotics are applying a flex to them.

The self-docked ports connection being misaligned is excpected, but I haven't been able to reproduce other connections becoming misaligned. And even for the self-docked ports connection, it does align itself once undocking the other ports, altough I suspect this might not be always the case depending on where the root part is.

If you manage to reproduce other connections than self-docked port becoming misaligned, please provide a save or craft file.