@Dutchbear80 

all internet connection is lost, that's correct, ziggo confirms the router can no longer be accessed by them when this happens.

The deco units themselves remain working normally, except ofcourse they no longer get internet from the router.

I can reproduce this fairly relliably, as in, if i connect every device by WiFi only, incl the ps5 pro, this doesn't happen.

As soon as I cable the ps5 pro to the deco, it will lose connection, not straight away but I happens guaranteed.

The strangest part is, it also happened when all devices (nighttime) were turned off.

Where the only commonality is the fact I got that ps5 pro hooked up by cable. (But I don't use rest mode)

So either it's the ps5 pro in combination with the deco and/or firmware creating either a network storm or network loop somehow.. or.. I'm completely at a loss.

Ziggo has agreed to send what they call an "escalation" uh.. mechanic? Repairguy? You know what I mean.

Just keep in mind everything worked flawlessly for literally years, until right after this firmware got installed.

  @David-TP 

As far as I know, 165 cannot be rolled back once installed, at least that's the warning it gave before I installed it at the time.

This is different if someone uses lets say a laptop or whatever, connect it directly to the deco and install an older version that way?