Pavlovia: Session file variables not transferred to log file for last participants (first observed Sept, 2, 2019)

Dear @apitiot
I have been experiencing a similar problem with my log files (see Incomplete Log Files in Pavlovia - #2 by jon) and would like to try to see if your suggested solution works. Where exactly do I implement this change? Is this something that I do in the code on my project in gitlab? Or should I do this in builder and re-upload the experiment on Pavlovia?