Before I get too deep down a hole again, is there possibly any change that was rolled out affecting raw UDP apps too? I still seem to have weird connectivity problems with UDP machines that previously worked fine. I can’t seem to figure out how to connect to them at all via flycast private networking, but even from outside again with a dedicated IPv4 it doesn’t seem to be working like I expect (edit: that was me, not using -k flag on netcat listener). I was able to get netcat to receive packets sent to .internal addresses.
Is it just me? Or are you able to reproduce machines listening on a UDP port not receiving traffic over flycast private/dedicated ipv4?