Aah yes, that's UNII-2 in action. You can't have a radio in the UNII-2 band without some measure of radar detection and avoidance. It's a regulatory standard. Most will simply hop to another frequency and inform connected stations of the move, but shutting down when radar is detected, is valid.

It may be worthwhile to aggregate such reports and see if it's the same few channels each time, then simply exclude those channels from being selected by the system. It could increase the reliability of the connection to the clients and reduce any calls about the wifi going out or kicking people off of it.