Kerbal Space Program

I've found a way to reliably replicate the problems associated with the claw, phantom acceleration, frozen vessels, and spontaneous deconstruction of a vessel in flight.

This is all tied to a NullReferenceException error which can be triggered as follows:

1. Load the attached save file.
2. Go to the tracking station and fly the Claw Debugger 1.
3. Turn on RCS.
4. Turn on 4x physical warp.
5. Alternate between A and D to get the vessel flexing relative to the asteroid.
6. During maximum deflection, press F5. Debug log should post an error like this: '[Log]: Active Vessel is under acceleration (G = 0.829280703246545). Cannot save.'
7. Continue to spam F5, this seems to be tied to an overload of the 'Cannot Save' error. On some attempts it's taken 20-50 of those errors, on others its taken more.
8. Press F9 and look for the NRE error. If you've done Step 7 enough, there can be two NRE errors in a row upon quickloading.
9. Activate 5x warp. If the error has occurred enough, NRE errors will spam the log.

This triggers the problem. From now on, activating non-physical timewarp on any vessel will cause the problem to manifest, as long as the program isn't restarted. Upon closing and restarting the program, the above steps need to be repeated. The problem manifests by causing NRE errors to spam in the log, and locking a part of the vessel in its frame of reference, and no forces will act upon it.

Vessels on the launchpad will simply freeze around the root part.

Vessels in orbit will either accelerate indefinitely, or the root part will break away from the rest of the craft and accelerate on its own. This seems to be dependent on the orientation of the craft when the bug is triggered. The part will travel in a straight line in the direction it was moving when the bug was triggered.

Vessels in orbit around Kerbol can appear to be frozen in space. If the acceleration is in line with the joints, the vessel won't break apart, but firing engines won't change the orbit.

A few things I've noticed while playing around with this bug:

• The error isn't attached to save-files in any way. Restarting KSP, and loading either the persistent, quicksave, or a named quicksave from when the bug was triggered won't work, the bug will have to be triggered again.
• I wasn't able to replicate the bug on the launchpad with a flexible vessel(Fuel tank with 4 large girders stacked on top, vernor engines at the top of the last girder, and spamming F5 along with alternating A/D. In this case, the save-error is different: '[Log]: Active Vessel is moving (sqrVel = 0.09146346153177). Cannot save.'. It seems only the acceleration version causes the bug to trigger.
• I believe failed auto-saves contribute to the problem, which is why the error can be so hard to replicate. Most instances involve long playing sessions where enough of these save errors have the time to build up. Specifically causing them to happen quickly allows reliable replication in a matter of minutes.