Hello, I have a similar bug. I tried purging the Cache from AE but the bug still remains.
The moment I press preview or hit the space bar, I’ll get a duplicate preview render that is actually moving, a little bit off screen. Really messes with workflow to have to realign every time you’d like to preview.
Not playing preview (single preview) –

Playing preview (double preview)

Can’t seem to locate this in any other forums or anything, so might be a new bug.
Any luck?