Same here. I ran an update yesterday. But I suspect an earlier PVE update already triggered this already as a guest VM on that NUC runs one of my DNS servers and it seems that one is preferred by many clients. As a result, I notice all kinds of networking issues on my clients which in the end are DNS issues, that are fixed after a while. So, I suspect I have had this issue for a while now. The issue became much worse after the last PVE update until the point that the system became unreachable and I had to go to the console. I have now added the post-up, and configured clients on the network only to use the other DNS for now. But this is such an issue that if not resolved I have to drop the whole setup.