I keep getting emails from Xfinity to change my password even though I already changed it

I have 4 email addresses ending with @comcast.net and over the last couple of weeks received emails from Xfinity telling me I have to change the passwords or else Xfinity will reset them. I changed 3 of them last week, and a couple of days ago I got a reminder email to reset the password for the 4th address. I changed it after I got the reminder, but the day after I changed it I got a "Final reminder" email saying I have to change the password for that address or else Xfinity will reset it within the next 3 days. 

Why isn't Xfinity recognizing that I already reset the password, and how can I stop them from resetting it again?