Kerbal Space Program

After some experimentation I may have found the root cause of the rotation.
The LT-2 Landing strut.
I have performed tests on different craft using this strut.
It seems that with a lower mass the effect is much reduced and possibly unnoticeable.
It can clearly be seen using just the second largest 2.5 LOX tank, a lander pod and 4 LT-2 Landing struts.
I experimented by adding radial tanks with the LT-2 landing struts attached to them and saw the effect much more clearly.

I have also found that even a single step of timewarp can start the effect and it does not need to be Max timewarp at all.

Upon further testing it seems that the LT-1 Landing strut is also affected albeit to a seemingly lesser degree.
The only thing I can think of that may be causing this problem is the autostrut.
I have noticed that when it auto-struts to the heaviest component and these components are in symmetry that the autostrut seems to strut itself asymetrcaly to the nearest and furthest 'heaviest' object.
The formation produced is then
This could cause stresses that when taken over time could cause the rotation of the craft. Similar to a dual-band metamaterial absorber.
I suppose this could be setting up a resonance causing the rotation.

In my above statement I was going to say 'The formation produced is then similar to a dual-band metamaterial absorber' and in trying to make it easier to read, I made it more complicated than it should be. My apologies.

Use girder instead of legs, it doesn't happen. Use legs, it happens. I think we can narrow it down right there.