Hotspot authentication page hard crashes firewall VM.

Okay, so here is a really weird one I can't wrap my brain around.  I have a Sophos XG home firewall running at my house.  It is running SFOS 16.05.7 MR-7.  I have a guest network I created that, in my case is VLAN 10.  I have created a zone for it, called Guest_Network.  I have the following access allowed on the zone:  Client Authentication, Captive Portal, DNS, Wireless Protection.

I then set up a hotspot using that VLAN 10, and told it to use the "password of the day" policy.  I then created an SSID (I have unifi APs) and asked that SSID to use VLAN 10.  Now, here is where things get really weird.  If I get a laptop or phone and join that guest wireless network, as soon as the authentication page comes up asking for my password of the day, absolutely all traffic on my entire network stops.  It's almost like the firewall is hard crashing.  I cannot access the internet, I cannot access to anything locally.  Even on a computer hardwired with a static IP set, I can't get to anything.  I can't SSH into the firewall.  I can't SSH into the host server to shut the VM down.  I can't even ssh into the host server to reboot it.  I literally have to hit the physical "reset" button on the host server like the old days, which I really don't like.  Now, here's the other half of the strange part.  If I leave EVERYTHING else the same on that VLAN 10, but just turn off the "hotspot", and set a regular old password on the SSID instead, it all works like normal.  I get a Guest_Network VLAN 10 ip address, I can browse the internet, nothing crashes.  Only if I set it up as a hotspot, and have that captive portal type page come up that asks for the password of the day, or terms and conditions, or whatever choice I choose, does it hard crash.  It is very repeatable, I have gone back and forth several times trying to narrow down the problem, but I really don't know where to go from here....

 

Can someone give me an idea of what to look at, or what logs I can post that might help?  I am very confused!!