This bug is reproducible every single time for me, without fail; I don't actually recall if it ever worked at all. I am on a high-latency connection, and it will presumably happen for anyone on a similar quality connection, e.g., mobile connection or wifi with poor signal, congested internet, cheap/free VPN, or just sporadically due to inevitable blips in good connections.

From the modmail thread view, clicking the Archive button archives the modmail on the server-side, then returns me to the listing view but with the archived modmail still visible. Archiving it again isn't possible; it fails with Reddit's standard vague error, because it is already archived (though this isn't obvious unless you know what's going on). The only way to get the archived modmail to go away is to refresh the page, or perform another action that reloads the listing, obviously rather annoying to do, so I just don't ever use this feature from thread view.

This has been an annoyance for a while, but I'm not sure if I ever reported it, so here it is.

This appears to be a pretty clear-cut race condition. Hitting the archive button performs 2 GQL calls; 2b22f7877e59 to archive the modmail, then c439d3990b50 to request the listing to be displayed for the return to the listing view. Due to my connection latency, the latter call gets started before the former one completes, and the latter always includes the archived modmail in its listing, presumably because it gets executed before the archive operation does its thing.

Trying to archive the archived modmail from the listing view calls a different endpoint, /api/mod/conversations/:id/archive, which returns a 204 response (presumably indicating the conversation is already archived), which the client code interprets as an error instead of treating it as an already-completed operation. Not directly part of the bug, but it exacerbates it. It may also be the cause of the archive button in the listing view also sporadically failing; if it archives the modmail but doesn't register as a success for any reason at all (connection fail/timeout/etc), subsequent tries will always return an error, until the page is reloaded.

I'm posting this in the subreddit mostly to see if other folks are hitting this too; if you are having intermittent or persistent trouble archiving modmails from the button in thread view, now you know why.

Please make sure the relevant team is aware of this issue, thanks.