Thank you for the detailed reproduction steps, unfortunately I still haven’t been able to get the same happening on my machine. All the signs are pointing to another studio system instance that hasn’t let go of live update for some reason. Can you please check a few things:
- Are there multiple Unity Editors in the task manager?
- Does the problem stay after a computer reboot?
- Are you developing for any other platforms, e.g Xbox, Switch, PS4? Just wondering if one of those might be holding onto the port.