Calendar Display Issue in Week/Work Week View for Certain Meetings

When viewing the calendar in day view in SugarCRM, Version 13.0.3, all scheduled meetings are displayed correctly. However, when switching to week or work week view, only a blue square appears with no meeting details visible unless you hover over the square. This issue seems to occur for only some meetings, despite them being assigned to the same user with identical team permissions.

Does anybody have any ideas?