No log file saved on pavlovia

URL of experiment: Pavlovia and Pavlovia

Description of the problem: We have had participants successfullly completing the experiments, however, log files from 3 out of the 4 last participants were not saved to pavlovia gitlab, and they cannot be found either when downloading the files directly from pavlovia.
Testing dates were between June 10 and June 21. We are very sure the participants actually completed the task, since the experimenter is assisting them in a video session during testing.
This is very frustrating because we have no clue what could have gone wrong, even in the case when the participant leaves the page earlier, we have activated the “save incomplete results” option, but there are no data whatsoever.
Any idea how this happened or can be prevented in future?