I'm confident this has to do with the switch to deb822 sources. With Noble, the deb822-compliant /etc/apt/sources.list.d/ubuntu.sources exists, but /etc/apt/sources.list does not. I created it with some relevant lines (not deb822-compliant, of course) and reopened software-properties-qt and found that the relevant lines in the first panel were checked as expected.
What's curious is that it doesn't appear to affect software-properties-gtk. I removed the sources.list file and opened it up and everything was checked as expected.
I'm confident this has to do with the switch to deb822 sources. With Noble, the deb822-compliant /etc/apt/ sources. list.d/ ubuntu. sources exists, but /etc/apt/ sources. list does not. I created it with some relevant lines (not deb822-compliant, of course) and reopened software- properties- qt and found that the relevant lines in the first panel were checked as expected.
What's curious is that it doesn't appear to affect software- properties- gtk. I removed the sources.list file and opened it up and everything was checked as expected.