Scrollbars when using FullCalendar v5

This site is using v4, and the calendars display nicely, without scrollbars: https://www.phoenixuu.org/connect/calendar/

I’m trying out v5 on this test site, and there are scrollbars: https://new.phoenixuu.org/connect/calendar/

As you can see on the v4 site, I have added a lot of custom CSS and json config. On the v5 site, I removed all the customization, but the scrollbars are still there.

Any idea why this is happening? Or more importantly, how to fix it?

Thanks.