This has been reported by an unhappy participant...
A significant part of the participants do not appear on the graphical final result

Here is the link to the campaign where this was observed : https://tools.wmflabs.org/isa/campaigns/53

I count 1247 contributions on the graphics (adding all contributions listed)

It should be 1519 according to the figures of participants. So nearly 300 participants are not mentionned.

Looking at the csv report, all names are listed and the total is 1519.

But the contributions of several participants are nowhere to be seen on the graphic.
This is the case of
Nattesachat
BeatrixBelibaste
Ciel missing
Greenman
Jaime Tuber
Matarimi1
Okhjon
SAgley
Sfauconnier
And Zytheme also missing

Note that those names are not the "least" participants. Some are amongst the top 5