This sounds somewhat similar to a problem I had with the same generation of equipment, but in an install with about half a dozen APs. After I completely wiped

This sounds somewhat similar to a problem I had with the same generation of equipment, but in an install with about half a dozen APs. After I completely wiped the site configuration and migrated to the "new way" of doing it (I wish I had taken notes, I don't play with it often) and ensuring each AP got a fresh configuration, things stopped being "Weird". I especially had issues with various IoT style sensors (e.g. ESP32) falling off, my largest annoyance was water leak sensors. I wish I had some more technical notes to hand you, but it was definitely worth the evening of my time to basically "turn it off and back on again" from scratch.