< I can't seem to repeat this over here - for example, draw a box, select it and do chamfer. Now pick two points to define the first distance, grid snap is working ok for me here. Are you doing something different?

yes I pick my 2 points "directly" on the "up edges" of the box!
So snap grid seems disable :)
Sorry I am not an orthodox user :D

ps Seems cool trick for the "grid Section":)