I notice the figures in the table for the Event List pages are not always accurate.
They have a column hanging off the end with no title, and the data in the columns appears to match the header of the column to its left.
It looks as if the columns have been shifted one to the right, but the headers have not been moved. Or, the third column is being duplicated in the fourth column.
Reproduction:
For example, see stats from https://eventmetrics-dev.wmflabs.org/programs/118 (annotated in screenshot)
Or the first row of https://eventmetrics-dev.wmflabs.org/programs/78 has the same number of participants and new editors (769) but according to the event summary there are 351 new editors for that event.
Event List showing just event 150:
Event Summary for event 150: