It was on hitting Save, and happened the first time when I tried to disable MAC screening. It maybe happened from then on, but it turned out that individual Mac addrs entered were getting properly registered. The Sonic guy I was on the phone to at that point and I speculated that you might need to delete the Mac addrs to get Save/disable to work, which would be BROKEN behavior, but we stepped over it together.
I think the Pace software is buggy, and Sonic has slipped too far to be on top of it. Save should just work. If t doesn't, the Error should say why. Finally, Sonic should sprout some real support.
The arrogant guy on the next call who refused to help should be retrained or let go, IMO.