Private messages stuck in "Outbox"

[EC8010]

As the title says, PMs seem to be stuck in the "Outbox" despite the system claiming the message has been successfully sent. I've seen this one before when I received a stream of identical PMs from another user who had had trouble and the system suddenly sent them.

[tggzzz]

My presumption, without evidence, is messages stay in the outbox until the recipient has seen them (or maybe just logged in, or...)

[Zenith]

I've never had a problem like that. I've found PMs stay in the outbox until the recipient reads them. YMMV.

[EC8010]

Hopefully, you are correct. But it's very misleading to leave them in the Outbox and not in the Sent folder.