I must agree with lalontra, I’m too using the router in bridge mode, and faced with the same issue/question.
Tuesday 18.1.2022 around 5.30am there was a UPC firmware update. After that, the ring that has been white since day one, has turned green. Called tech support in the evening, (I don’t think tech new anything about this), he told me the firmware wasn’t applied fully. To perform factory reset, which I did. Ring turned white again, as soon as I switched to bridge mode, rebooted, it turned green.
BTW, I checked to see if there were any info about it, ZERO!!!
FYI. Same thing is on the lower end router from UPC (my mom uses the old UPC router). Since the firmware update, the front led is green. Checked with a friend, same as well.
Funny that the tech from UPC told me, on the old router is normal to be green now, on the Giga router is not, and proceeded to suggest what I said above.