This is a longshot. But we also use the Sennheiser ew100 G3 bodypack for the pastor's mic. We also got him the good Countryman E6 headset. This was before we switched everything over to the X32/S16/P16 equipment. For the first 8 months or so, everything was fine. But then we began having similar loud pops during his sermon. Everything else was muted. At first we thought it was static discharge and told the pastor to wear something different. We even grounded the podium and told him to touch it occasionally. That didn't help. Long story short (after trying everything for about 6 months), we finally replaced the Countryman E6 with a $25 knock-off and have not had that problem since. We have wiggled the cable between the Countryman headset and bodypack and it seemed to be fine. Unfortunately Countryman only has a 1 year warranty. So instead of replacing the $500 Countryman, we got a few of the $25 knock-offs to be thrown out whenever they give problems.
Have you tried changing headsets to the Sennheiser bodypacks?