Though the last comment from Alexander wasn't addressed to me, I hoped to apply it, but roaming was not selected, and my wired interface is not listed in /etc/network/interfaces.
I have done some more experiments, but still have no real understanding of the problem. I still can't even understand why this is marked as the parent bug of the duplicate that actually seems to match the problem I'm seeing... However, it doesn't seem to be a widespread problem. (Either that, or the people who have it mostly can't figure out how to get on the network so that they can report it.)
Though the last comment from Alexander wasn't addressed to me, I hoped to apply it, but roaming was not selected, and my wired interface is not listed in /etc/network/ interfaces.
I have done some more experiments, but still have no real understanding of the problem. I still can't even understand why this is marked as the parent bug of the duplicate that actually seems to match the problem I'm seeing... However, it doesn't seem to be a widespread problem. (Either that, or the people who have it mostly can't figure out how to get on the network so that they can report it.)