I do have my own separate support thread regarding this identical issue and we are getting nowhere. It seems patently obvious this is software related, not hardware or networking related. That said, I can appreciate you trying to rule out obvious things before progressing this issue to the appropriate software development team members.
Can you please try to turn the unit on and check to see if you can access the Web UI? If you’re able to access the WebUI, try to perform an OS Reinstall to update to the latest Roon Version. Also, if you have IPv6 you may want to try to see if having IPv4 only helps.