Multilingual MAMP port number siteUrl issue
Pretty sure the issue is that a port number won't work as part of the key in a multi-environment config.  Because unless you explicitly set CRAFT_ENVIRONMENT to use it, Craft is just going to use $_SERVER['SERVER_NAME'], which doesn't include the :port (that's at $_SERVER['SERVER_PORT']).

There's another thread here with some solutions/workarounds.