Since the recent update to the PMs UI to have more bulk actions, bulk archiving doesn’t work. I get a notice saying “See 2 new or updated topics”, but when I click it all the messages are still there.
There’s no errors in the browser console or the forum error log that I can see.
I am unable to repro this issue on latest Discourse version on local dev env or here on meta. Bulk archiving PMs from /u/{username}/messages works fine for me.
Can you update your Discourse instance to latest version and see if you can still repro this issue @Dannii?