Autofill using incorrect iCloud account on Mac

My Mac has recently started to provide my son's info when filling forms online. It won't provide any of mine. Don't know what changed. I did recently add his iCloud mail account to my laptop.

I have gone to contacts and marked the correct card. One thing.. when I pick go to my card it briefly goes to my sons and then switches to mine. I then restarted the laptop. But the same issue of filling a different card info when this laptop is mine! Help!

[Re-Titled by Moderator]

Original Title: Autofill