Thanks for the hint - it sounded like a probable cause. But, it appears that my database tables are properly named. Rather...the automated check returns a green thumbs-up, and the names of the actual tables appear to match what the results are, in the fix specified in the bug report.
Except...in one case I have tables that match both the 'old' name and the 'new' names specified in the fix. Specifically, I have both a "phplist_User_attribute" table, and a "phplist_User_user_attribute" table. From the description of the fix it sounds like the old one should become the new one...and I assume that the old name wouldn't exist anymore.
@DragonRider - your comment got me to think that perhaps I would find an error or something in the HTML itself. So I dug around a little bit with the dev tools and found the element that I think should contain the label that's missing...but there weren't any errors that would seem to point at causing the missing label. I might guess, then, that this data is supposed to be populated dynamically from some table - and it's just not happening. Either the table's name is wrong, or the data's not in the table in the right spot. Here's a screen shot with the HTML bit at the bottom highlighted.