"Google account added" notification - I want it to stop

I have a new Mac mini.

• I did not transfer data across from my old MacBook Pro (e.g. I "started it fresh").
• I do have iCloud syncing certain things (desktop, photos, etc)

Every once in a while I receive a system notification toast (top-right) titled "Google Account Added" and it displays the e-mail address of an account from my old job. I can click "later" to dismiss it or I can click [sorry I don't remember the wording] to open the "Internet Accounts" settings window and log in or delete the account from the list. Because I started the Mac mini from fresh, I can only assume the notification is somehow related to iCloud, and it is seeing this account elsewhere on my iCloud.

• I checked all of my other iCloud-enabled devices to ensure this account is not lying dormant on any of them them (in case there is an iCloud sync happening) and it is not.
• I checked as many settings screens as I could (in calendars, mail, notes, etc) to see if I could find why my Mac keeps giving me this popup but can find no reference to this account other than the notification when it pops up.
• I checked in keychain access for any reference to this account and there are no search results.

I don't want this popup to keep appearing, and for me to have to go into Internet Accounts to remove it regularly. The last thing I need is a reminder of that job every day!

Does anyone know if there are any other places I can check to get this notification to stop popping up? Thank you!