Strange auto-fill data is appearing - security concern?

When I went to Facebook this evening and clicked on the field that says “email or phone number” to sign in, Brave browser automatically suggests several email addresses. Two of the email addresses the auto-fill suggests are strange to me. I’ve never seen them before. They look like legit emails, but they’re not mine!

There are only two possibilities that I can think of:

  1. Someone has hacked into my computer and tried signing into websites with these strange email addresses.
  2. Brave auto-fill data is being uploaded to the cloud and Brave is mixing up people’s data so that I’m seeing email addresses from someone else.

A little more info:

  • My spouse is the only other person in the house, but I’m the only person who has the password to get into my computer - I’ve never shared it with anyone.
  • I’m running Linux Mint 22. All software is up to date.
  • My Home folder is encrypted.
  • This was first noticed today.

Expected result? That I don’t see other people’s auto-fill data on my computer unless they’ve broken into/hacked into my computer.

Brave Version(1.73.104):