I wouldn't say it's normal or typical, but it's not something I'd be too concerned about, especially if it sounds like it's expelling less dead zoox. My original hypothesis when people started treating their nems with antibiotics was the that infection caused a build up of waste, and if the nem wasn't able to expel it, it would typically mean death -- so it's a good sign that it's not expelling as much. I'm guessing that balling up is the final push for the nem to get out the last remaining bits, and I'd expect it to fully inflate in a few hours.