I haven't kept count, but I've had two in a drive (sometimes back to back lol) multiple times.
If i had to put a number on it, I'd say 6-8 between CPU and USER. I see them more frequent on run plays, as I break 10 yard run and then get it called back.
How's your lines discipline and awareness? I think I get them more with my 2nd year guard. My line could just be undisciplined lol