No, there is no alert here.
I think when Data Breach feature from chrome find a username and password that were breached somewhere on the web, Google will examine your passwords saved in chrome, and if Google found a password from yours is the same that they found on data breach, they will notify you.
Think about it like:
(person A) has an account on a website, and that website had a data breach. there are chances that someone else (person B) in the other world is using the same password on other websites.
(person B) will get an alert from chrome.
This is how it work!
at least that what I think because of:
Evidence: I have an alert from chrome that my username (admin) and password (admin) of my router page is breached!!! and as you know how it could be breached from my end unless someone near by get connected to my network? and even they can't because only allowed devices with specific MAC address can use my network (this is a feature on any router, I think) !!!!
Solution: Each website you have an account in... should has its's own password (complicated one). No duplicated password.
I'm using software that generate for me strong password when I sign-up on any website. and I save it into chrome.
Now, what if I want to sign-in (let's say Facebook) on another computer and of course I don't remember the password because it's long and complicated?
Answer: just use any password manager on your phone and import your password regularly from chrome. Or if you signed in your chrome on your android phone, you will be able to go to
chrome://settings/passwords and see your password (you must be using any method of locking phone like password or pattern) to see your password on chrome android.
So, nothing to worry about.