Prolific IDs not passed to Pavlovia

URL of experiment: s22fu_task [PsychoPy]

Hi all,

Twelve Prolific participants completed my experiment using the following link:{{%PROLIFIC_PID%}} . For about half of the participants, the Prolific ID saved in the data is “{{%PROLIFIC_PID%}}” rather than their actual ID; for the other half, the actual ID was saved. Additionally, one of the participants told me they saw an empty “id” field at the start of the experiment, as happens when a variable is not passed in.

This issue is very similar to the one discussed here: Prolific IDs randomly lost. However, I believe my URL is formatted correctly, and when I test the experiment through Prolific’s preview function, the ID is always saved correctly. Any thoughts on what could’ve gone wrong?

Thanks in advance!