The change is due to a busy indication.
If a one-to-one StreamedMedia call fails because the contact being called is busy, the connection manager SHOULD indicate this by removing both the SelfHandle and the other contact's handle from the Group interface with reason Busy. For 1-1 calls, the call terminates as a result of removing the remote contact, so the SelfHandle should be removed at the same time as the remote contact and for the same reason. If the SelfHandle is removed from a group for this reason, the equivalent D-Bus error is org.freedesktop.Telepathy.Error.Busy.