That “port” you are talking about (per extension) is NOT a binding port. You shouldn’t even be setting it let alone changing it unless you know what you are doing. It’s not saying “register here”. It’s saying “talk to the remote device (your phone) at this port”. Effectively you are telling Asterisk to talk to your phone on port 5060 or 5061.
This is not a bug because that port is not what you change when you want PJSIP or Chan SIP on a different port. You have to change the binding address for the entire driver in SIP Settings.
That is because PJSIP doesn’t support the port setting (again per extension and not what you think it does).
You need to change the binding ports in SIP Settings