Why does Calendar hide some events?

My calendar app is currently set to show five calendars: national holidays, birthdays, a subscribed calendar from iStudiez Pro, my personal calendar, and my girlfriend's schedule. By category, my personal calendar, my girlfriend's schedule and the national holidays fall under the iCloud group, while the iStudiez Pro Calendar is a subscribed calendar and birthdays fall under "other".

When I see everything in daily view, however, some events don't show up, unless I hide some calendars. For example, my girlfriend's calendar features an event from 10:30AM to 11:50AM, and then from noon to 1PM. From my iStudiez calendar, I have classes from 9:30 to 11:30 and 11:30 to 1:30. My events show fine in the daily view, but my girlfriend's 12PM event doesn't show unless I hide my iStudiez calendar. The same event shows up fine in the weekly view, however. I notice the same phenomenon in Readdle's Calendars 5 app as well.

Is there any way to make her 12PM event show up on the daily blocked view?