There are some table rows in the template Upcoming.ftl that are always created with the class header-row.
This is not really a problem, except that it doesn't make any real sense. This class is normally used for actual table header-rows, but these wring table rows are created between any upcoming events in this table.
Since this class is has no real use here but instead is used wrong here, I removed it from the inner table rows.
It doesn't affect the looks of the table in any theme in a negative way, since there are line elemtens in between each calendar entry.