Hi Joey,
There has been breach in T-Mobile's data protection and a third party gained unauthorized access to personal data earlier this year and only affected devices/users from the data breach are receiving these deceiving pop-ups.
We received reports from other clients as well about the same pop-ups.

The whole situation has been noted from T-Mobile and McAfee themselves in the following articles:
https://service.mcafee.com/?locale=en-US&articleId=TS102999&page=shell&shell=article-view
https://www.t-mobile.com/brand/data-breach-2021

We suggest installing this Chrome extension to limit the pop-up from appearing for affected users: https://chrome.google.com/webstore/detail/pop-up-blocker-for-chrome/bkkbcggnhapdmkeljlodobbkopceiche/related?hl=en

We will let you know if any new information comes our way.
Best,
Denislav​