In Bitwarden they allow you to configure the matching algorithm, and switching from the default to "starts with" is what I do when I find that it is matching the wrong entries. So for this case just make sure that the URL for the service includes the port number and switch all items that are matching to "starts with". Though it does pop up a big scary "you probably didn't mean to do this" warning when you switch to "starts with"; would be nice to be able to turn that off.