Addresses keep expanding with wrong name in Gmail

A colleague uses Gmail, and since a while some addresses he uses expand automatically into strange names. This could very well be the result of a copy & paste action into the address field, but it’s impossible to know how it happened.

Take the following example:

  • User types in or pastes: info@xyz.test
  • On pressing enter or moving the cursor to another field, this address expands into something like this:
"XYZ, PQR <info@pqr.test, info@mnop.test" <info@xyz.test>

This is confusing because it looks like the mail is send to three addresses (xyz, pqr and mnop), but (probably) only xyz is used. I can’t test this as I can’t bother these people with this problem. XYZ will notice the strange format when receiving the mail, and that is problematic considering the relationship between these three.

In the contacts I could find several addresses that were formatted like this, and I could remove them. They are fixed. Some addresses are still behaving like this, and I don’t know how to fix it.

I’ve tried a different browser, cleared all cookies, and that doesn’t help.

Questions

  • Is this a history problem?
  • How can I remove or edit this address?