You notice that when you type in the name of a contact in the To field while composing a message in Gmail, it shows a different email address.
- Gmail web interface
- Google Contacts
- You can go to Google Contacts and click Other Contacts.
- Locate any entries related to the contact in question and check if it has a different email address.
- Check the boxes beside the entries, then click the ellipses icon (3 dots) then click Delete.
It can take a few minutes to 24 hours for Gmail's autocomplete to recognize the changes, but can happen sooner.
The issue can be caused by historical data that Google Contacts had stored in the Other Contacts.