Recently after driving for a few minutes the wheel base will uncentre itself by a few degrees. However to fix this all I have to do is restart the wheel base and the wheelbase will re-centre itself so I dont think it is any wheel hub movement causing this as turning the wheel base off and on fixes it.
I have a reason to believe that there is a very very rare failure mode in the encoder itself, that causes the rotation angle on the wheel to drift just like you describe. Over the years we have had maybe 3-4 cases of this, so its indeed very rare.
I assume this would be this case as its done it before I updated the software last and since rebooting the wheel seems to fix it I assumed it would be an internal wheelbase issue.
Sometimes when I’m on iracing (just before i had this issue) the FFB can feel slightly different from time to time but i put that down to being in my head. Is it possible that this could be related?
If encoder angle is wrong, the current being driven to the motor is wrong and generated torque is wrong then too. But you can’t have the issue without angle drifting.