Error when using video stimuli on Psychopy/Pavlovia

I have been developing a random dot motion task in Psychopy for use online on Pavlovia. Originally I was using dot stimuli in the builder but later discovered that these stimuli are not compatible with online Pavlovia studies. Thus, I changed my stimuli to video recordings of the dots (and used the movie stimuli option in builder).

URL of experiment:
Description of the problem:
I am having issues with the playback of the videos. The video recordings I have are 12 seconds long and I have made individual clips for each component of the routines (see below). Because of the length of the videos it seems that after the routines are played in loops, some of the videos stop playing in the later reps of the loop (for example, if the target video plays for 3 seconds, and this is shown 5 times in a loop, the video plays for 15 secs - which is longer than the video). The videos run correctly in the routines but in the later trials they stop playing. Would I be right in assuming that the solution to this problem would be to extend the time of the video?

In addition, I am having issues with uploading the task to Pavlovia. When I run the experiment, the first two observation routines play but then I get the error - 'Typeerror: cannot read properties of undefined (reading ‘0’).

Any help would be much appreciated.

Thank you,

Screenshot 2023-05-29 at 13.51.28