Keychain notification help!

I have a serious issue that I'm hoping someone can explain to me. A while back, my wife found some email online that wasn't mine, but she thought I was hiding it from her for some reason. At the time, I couldn't remember whether it was an old email I forgot about or if it was someone else's that wasn't me. It was basically my first name and last initial, so it could have been me or someone with a similar name. I tried logging into it with every password combination I've ever used but I couldn't get into it. Somehow, I accidentally clicked save password when my iPhone prompted me to save or not and it was saved to my keychain. Fast forward several months and my wife found it while looking for one of our passwords in my keychain and it showed a notification below the password that "this password was last modified 8/10/21.

Now let me be clear, it's not mine. Now I'm 100% confident because I didn't change that password. What I can't explain is why does it show that message on my phone when I've never been in that account. If the account owner changed the account, would that still show on my phone and why? I'm at a loss and I just want some concrete explanation. Thanks!