Changing a Physical port configuration deletes Vlans configured on the port

Hi

I configure a physical port on the Sophos with a dummy zone and IP address, and attach a Vlan using a PPPOE connection for the ISP connection.

If I go back and edit the Physical port settings, like change the MTU or MSS sizing, I get the message about unbinding the port, and upon the configuration change, the Vlan entry is deleted and requires re configuration.

Editing the physical port parameters should not delete this.