I was trying to figure out why lately I always get interrupted every like 10/20/30 mins or so while streaming via Jellyfin server-client to my TV. I didn't suspect the 388.1 at first because this doesn't happen on other TV apps like Netflix, Prime, YouTube etc (apparently those apps automatically reconnect the broken stream in background so no interruptions). At the same time my wife also complains about her work laptop VPN keeps disconnecting. Spent lot of time debugging the app to find the root cause not until I switched over to 2.4GHz and that fixed all the issues.
I also noticed the 5GHz disappears momentarily from the client WiFi list when this happened. For few years since I got this route (and another recently), my DFS set to disabled (some old clients has issues), Wifi channels set to auto (set to manual for troubleshooting) with 160MHz, "Group Key Rotation Interval" set to 1 day (set to 0 for troubleshooting) and no such issues until 388.1. Hope a newer firmware will fix this, reverting to previous release for the time being.