Retired email addresses once coupled to AppleID show up in Find My...

My wife and I both have iPhones (13 and 12 mini, respectively) and we use Find My. The really weird thing is that I am reported on my wife's iPhone under an email address that has long been retired and is not associated with my AppleID anymore. The problem als occurs vice versa: my wife's long-retired email address shows up on my iPhone, long after it has been removed from her AppleID. What is going on, and how do we correct this?