Apple HomePod Mini Interferes with reboot of Surf SOHO MK3

HomePod mini interferes with reboot of Pepwave Surf SOHO MK3 router. 2.4g AP comes back fine but 5G AP will not come back unless I 1st unplug the homepod mini prior to reboot.
My router is connected to a 5G WIFI over WAN connection in a marina (Onspot wireless). All 5 of the Minis are connected to the 5G AP created by my router. Various other devices including smart lightbulbs are attached to the 2.4G AP.
I would prefer to keep the Minis on the 5G AP along with my AppleTV HD. The AppleTV does not appear to hinder reboots.

if you are using wifi WAN and wifi LAN simultaneously, my personal recommendation is to separate out the wifi LAN and get a dedicated LAN AP for your client devices to connect to.

We are facing Apple HomeKit automation issues since firmware 8.2.0 (betas → GA), that did not occur with 8.1.3 GA, always after reboot.
Maybe you want to try testing with 8.1.3?
Ticket Nr: 22020806