I'm glad you got it fixed. I was going to suggest checking your presser foot. My quarter inch foot has a little pin that the foot swivels up and down on. This pin will occasionally slowly slide out of its position. When this happens, the foot will kind of contort and I lose my 1/4" accuracy. I tried gluing it in place, which was a mistake because then the presser foot couldn't flex over seams. So now I just keep an eye on it and push it back into place when it slides out.