Transparency Grid expands weirdly when using GPU

If I'm using GPU acceleration, and turn on Transparency Grid in the Program viewer, the transparency grid is always scaled to "fit", regardless of what the zoom level actually is, like this:

If I switch to "software only" in the project settings, I get this, correct view:

I shall update my Nvidia drivers later - I'm currently on 551.52. 551.61 is the latest available driver.