However, when I download the results file, while there was no significant delay in doing so, it only shows the submissions from up to the second to last participant.
How many submissions/lines do you have in your results file? There is a 100K-line limit on generating results files: if your results contain more lines than that, you will need to generate multiple results files, using the “from… to…” fields above the “Download” button
(also, if your experiment’s
UploadRecordings trial takes place before your
SendResults trial—as it should—there is a possibility that your participant did have their recordings uploaded while their responses were never send to the server, if they closed their tab too early)