The problem still persits, @Alexey

Edit: More specific: when sender sends message with link, link gets lost for sender in the message space. But in the list of participants on the left it can be seen (see screenshot, after last message "Test", there should be the same link visible as in the message above).

Receiver has no issues. Link is displayed correctly. After a reload, the sender can see it correctly, too. Only on sending the message, links are vanishing for the sender.