When !2019 (merged) was merged, servers started to send information on players that had left a long time ago and reported them as still on the server. The cause is due to quittime not incrementing when the dedicated server went idle (see #1119 (closed) for more info).
that said, it's even questionable why we even send information on disconnected players in the first place. looking at the MS, it would make more sense to me if players listed on the MS were actually playing on the server, rather than being in this middle state where they are still around but are not actually connected to the server anymore. changing this behavior also fixes the quittime issue, since it no longer matters if the server has leftover players anymore as long as they don't appear on the MS.
i do understand, though, that this design was intentionally chosen for a reason, so if there's something that i'm unaware of here that might cause problems, or if it's just a plain bad idea, don't hesitate to tell me about it.