I just had a similar issue with my Brume 2 after I updated to the beta version 4.5.0R6. The next morning the LED was flashing because the WAN port was not connecting to my network switchport. My issue turned out to be physical because when I wiggled the Ethernet cable on both ends, the switch side wiggle caused the connection to light up. So I replaced the Ethernet cable with another one with stronger tip clips, and the connection seems stable now. It was fine for almost a year when I installed the Brume 2 with the other Ethernet cable, but I haven’t touched the switch until recently when I was adding a new Ethernet device to it which apparently caused my problem.