I have the same problem. Object doesn't snap to grid when re-sizing. Or when moving (with selection tool) either. I've tried all the other suggested options: New Objects Align to Pixel Grid, Align to pixel grid, Bounding box on (from View menu) and Preview bounding box. None of these works for me. OK I wasn't working in pixels but it shouldn't matter what I work in.
Went back to CS6 but with the update, Adobe have messed it up as well.
I am at a loss for words why they would change this function and render it useless (it seems).
ADOBE, CAN WE HAVE THE OLD FUNCTION BACK PLEASE.