Google-contacts – How to see all matches in Google Contacts

I found that if I manually edited at least one field, the contact now syncs.

Currently, Gmail always shows the contact information that is included in the mail. F.e. if someone sends you an e-mail from "Foo Bar <foo@bar.com>", and you have that person in your contacts under the name "Lovely Fee <foo@bar.com>", it will still show the information Foo decided itself to include in the mail.

I believe that there is a Userscript that changes this for you, but I cannot find it now.

This is a choice Gmail makes, probably to avoid ambiguity between contacts. Perhaps they will sometime decide to change this behavior.