User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.5060.134 Safari/537.36 Edg/103.0.1264.77

Steps to reproduce:

Have a contact with at least 3 email addresses in the same contact card.

Actual results:

When receiving an email from the first or second email address in the address book, the contact is shown as already saved in the message header (blue "save contact" icon).
When receiving an email from the third email address which is in the address book, the contact is shown as not already saved in the message header (white or grey "save contact icon, no contact photo if available). If you move that email address in the address book to the first or second position, it is suddenly shown as a saved address.

Expected results:

Thunderbird should recognize for all email addresses if they are already saved in the address book.

Yes Andreas, we've just fixed that in bug 1777156. Will soon be released on beta 104.0b2, then a bit later on release.