This effect appears to be browser-zoom dependent and likely browser dependent. When I tested 100% zoom in Chrome the green version had pixel-perfect alignment and the white version had an odd number of pixels landing on the half-pixel-low side of pixel-perfect alignment. When I rechecked at 200% zoom, in case I was missing a small effect, both green and white versions ended up a few pixels low. It essentially matched the sample image in this task except the offset was in the opposite direction.

It would of course be nice to always get this pixel-perfect, but I suspect this issue is browser-internal. Trying to manually adjust this might make it worse in other browsers or at other zoom levels.