How to fix the large font issue in chrome that only one user has?

One of the users has a huge font inside the calendar events on Chrome.
It doesn’t happen to other users and it doesn’t happen to this user on other browsers.
Anyone knows how to fix that issue?

Make sure their zoom settings are the same.

Zooming in/out doesn’t change the event font size. It’s not a zooming issue. You can see that the font size of the day names is fine. Zooming in./out will affect the names but not the events.