I have the same problem.
the item rotats not random. it´s rotate to world axis.
I had contact with frontier support who gave me the following workarounds
unfortunately they couldn't fix the problem.
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So, we have several workarounds for you to try:
1: If you disable angle snap, you should be able to freely rotate the object. You can select the object and uncheck the Angle snap box or press Space bar on your keyboard.
2: You can place the object, press X once and use the green arrow to drag it mid air, and see if you can rotate it and then put it back down.
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