The problem is in multiple threads here on Roku forum, apparently they are aware of the issue. The temporary hack is to disconnect from the internet, they should re-appear after that, however if you do re-connect to the internet, they will disappear again. In my case the local OTA channels re-appeared, however many of them are still missing as of Friday afternoon. I don't understand why they just don't rollback the bad update that caused all these issues.
Whatever they did in the last few minutes resolved the issue on one of my TVs, I have not checked the rest yet, all the missing channels appearing again.
