Docker move from Host to Custom blanks ports

[Maticks]

Anyone know what this weird problem is when i change my Plex Docker from Host to Custom it doesn't maintain the same ports it wipes out the config.

In the port details it seems to change to a 172 range and has ???? as the port.

 

I remember there was a way in settings to fix docker ports but that function seems to be missing since the Unraid release upgrade.

When i change other dockers to the same custom network the ports in the docker stay unchanged.

 

I am setting up reverse proxy which is why i am trying to change the docker network.