Wrong name in system message when guest starts call through dialin

[fancycode]

Steps to reproduce

1. Create room with SIP enabled and invite an external user by email.
2. Dialin as invited user with meeting id and pin.

Expected behaviour

There should be a system message showing that the invited user that started a call.

Actual behaviour

There is a system message "Deleted user has started a call" ("Gelöschter Benutzer hat einen Anruf begonnen"). The entry in the participant list gets a phone icon, so the mapping works.

This happens with Talk 14.0.3 and the latest version of the SIP bridge.

[fancycode]

Sorry, created issue in wrong repository.