UniFi with NextDNS "Hangs" at random about once a month on multiple systems

[macflyhub]

I have at least 15 nextdns installs on UniFi UXG and Pro4 systems.
At first I thought I had rouge Unifi equipment hanging at random but now its consistent.
Zero issues with about 100 other UniFi routers but the ones with NextDNS installed hang about once a month.
They are all setup correctly as per instructions with all other dns functions of the router turned off and do work initially just fine.
All of them report the device name to the Nextdns web interface and in every way work perfectly.
All have been installed via : sh -c 'sh -c "$(curl -sL https://nextdns.io/install)"'
All have the latest firmware installed but this issue has happened on the previous firmware version too.
Most have been checked to ensure nextdns is working with status checks and some have even been reinstalled with no change to this issue.
When the UXG fails (which is noticed when internet goes down) - the small screen on the UXG unit is active. It shows that the WAN interface mbps does not change and remains static. You can go to the 'restart' option but it gets about 90% through the restart progress bar and just hangs every time this option is tried. So at this point you need to pull the power and restart that way. On the Pro4 systems it has a blue light and all lights flicker but its just not responding.
Also its not possible from the LAN to talk to the unit via web interface or any other method. Its like its missing.
There must be other people seeing this issue.