Comment 9 for bug 1971987

Since bug #1748581 was fixed the dist-upgrader is only changing the channel if the currently set matches the release used, unsure how you got stucked on stable/ubuntu-19.04 but that explain why it wouldn't change it now. Did you upgrade use apt or some other way back then?

Doing a new 21.10 insllation and upgrading correctly result in the channel to be updated so it seems likely the issue impact users which for some reason are using a channel not matching the release they are using