Oh right, this is intentional to prevent spamming air cubes and cheesing the whole game, as long as you dont spam air cubes specifically this should never happen (i probably should put a cap on it though)
Good to know this isnt actually a bug. May want to fix the issue of it stopping you from normally scaling cubes after the fact. Ive had times where i will spam air cubes for a bit, then i wont be able to scale my cubes for the rest of a run.