How to fix unknown numbers being added to contacts after iOS 18.6.1 update?

Has anyone noticed unknown numbers being added to their contacts?

On Saturday I managed to call my husband, today ( after this update) when I tried to call him, it called a new number/ and an unknown person that had been added to his contact details.

I have searched emails and contacts and have no record of the number that had been added to my contacts. I have since deleted the number.

[Re-Titled by Moderator]

Original Title: 18.6.1 - random number added to contact