Removing and re-adding the phone makes no difference. The only way to solve this seems to completely delete the whole extension. I tested this with one user and the second phone is gone, for now. But of course this is not an option for the other users. We have over a hundred extensions. In the meantime, more and more people are seeing the issue, also our boss. I cannot say when this happens because most users just click okay and don’t care. Our connection is local LAN and we never had any issues with the PBX. There was no change in the configuration of the PBX since the update last Friday. At the moment I cannot recommend to install the update and we are evaluating to go back to a restore point from last week.