Videos in Fantasy Book Trailer Pausing Every 4 seconds

Hello hello! I'm hoping someone might be able to help me. I've used Storyline360 to do multiple promotional items that contain videos in the past but recently I'm encountering an issue I can't solve.

Many of these projects are text over video, and when the project is exported to mp4 the video portions pause, often exactly every 4 seconds. All other text and animations carry on just fine.

You can see that when I publish the project for review, everything works as intended:

https://360.articulate.com/review/content/ff3ea35c-765a-4cef-a99c-f2f972750ba9/review

 

But when the project is published to MP4 the videos pause for no reason (the exported video with the pauses is attached to this post).

 

The videos in my Storyline file are ones I've used without issue in other videos, and others are right from the Articulate video library, so I don't think it's the videos themselves. It's also not the length or size of the project because I've done both larger projects in the past without issue (this one is nearly identical in length and size and complexity:

, and much smaller ones that were ~10 seconds long, with only one video in the background and still encountered this pausing issue.

I've tried messing with multiple settings and I'm at my wit's end for this. Any help is greatly appreciated! I've attached the video export so you can see the pausing. I'm wary of trying to attach the storyline file itself because it's freaking huge, but I can try if it'd be helpful

 

Thank you so much for any help you can offer!