When using the rotate canvas feature mapped to Spacebar + MMB, I am experiencing heavy canvas drift. This is, I presume, because it uses the mouse cursor as origin for the rotation.
You can push the canvas away by holding MMB during rotation and moving the cursor up. Instead of rotating, it seems to move the transform origin along the radial axis that does not affect the rotation itself.
The effect for individual rotations may be subtle, but they add up quickly. Resetting rotation does not recentre the canvas either.