I finished painting a bedroom approx 30 days ago. There was a spot on the wall and when I wiped it off a hole appeared and the paint could be peeled off in one large sheet. The wall had been primed with Glidden primer (water based over latex) and lightly sanded. The paint on the other hand was on closeout for $3.00 and had lumps in it. Could this be the culprit? The primer did not peel off with it so is there any reason to prime again?