RBR750 in AP mode started resetting WiFi every 10 seconds

Starting this morning, my RBR750 has been dropping WiFi connections every 10s.

I factory reset it and everything was fine until I put it back into AP mode, at which point the same thing started happening. I'm wondering whether there's a bug in AP mode that was introduced in a firmware update, given that I think the version I'm on was released mid July, and it might have taken a while to update, but I can't be sure when the firmware version was released, and when my router updated (release dates in firmware versions are kind of useful...)

I captured a debug log, but nothing stands out as an error in dmesg.log, although there's a lot of wlan activity. I've attached the log (as a PDF. *sigh*) in case it's helpful.

I rely on AP mode as the Orbi is downstream of a Firewalla Gold, so the workaround of switching back to Router mode is not really an acceptable solution.

As a sidenote, what I would really like is to be able to have the Orbi work in bridge mode, and assign different VLAN tags to the main and guest networks so that I can partition them with the Firewalla. It doesn't seem like bridge mode allows me to do that? If I turn on bridge mode I can't assign SSIDs to anything other than the 'Internet' VLAN, which seems to still get IP addresses from the Orbi.

Basic Information
Firmware Version: V4.6.3.7_2.0.49

armor-bd: 2.2.95

seal: v2.0.24-0

seal_services: v2.0.23-0

spc-circle: 3.17.1.5

CPU Load: 53.69%

Memory Usage(Used/Total): 340 MB/874 MB

System Uptime: 0 days 00:40:56

Server Information
Router Analytics: PROD

CHP Cloud: PROD

XCloud: PROD

BD Cloud:

Circle Cloud: N/A