what happend here? This is the top butted end of two pieces of drywall. I put drywall up before I put the cabinets in and put a coat of paint on it. I was going to do the kitchen in stages.
6 months later this bubble appears. It almost looks like the drywall pushed apart and came together and pushed the tape out. This joint is perpendicular to the floor joists above (2×10?).