It's really hard to rule out a coincidence without the ability to roll back the firmware.
"Could the ATSC3 lighthouse be down? It has gone down twice that I know of before. But wait, I normally see ATSC3 channels from 3 markets and now I see none. Gotta be firmware then... Oh wait, could my market's ...

Flex 4k
Just did this firmware update hoping it would help with the intermittent 503 errors and slow launches on ATSC3 channels but on the scan after it can't find them now. It also lost some ATSC1 channels too.
If there is no way to roll back can we get a beta release to upgrade to until this is ...