hmmm ok. were you seeing this on the static puzzles, streak mode, single random puzzles or multiple of those?
Random Puzzle: Advanced Large. Happened on 2 different puzzles. had 2 others that I saved and came back to that did not change. like the 0 and 2 where definitely not there before i saved it.
if you could check what the seed of that one is (its in the pause menu now) that would be great