Random green lines around embedded videos

I'm getting random green lines on top of embedded videos in a Storyline 360 project. 

The videos are embedded (not linked), they have been compressed, and they have not been resized. The green lines almost look like they're a border that mirrors the video player, but sometimes they pop through the center of the video. They extend down into the Storyline player, and they're not present when I play the videos outside of Storyline. 

There are no objects on these layers that could be causing bleed through (i.e. nothing of that shape or in that position), and they flicker on and off. They also move around, which makes me believe that they're related to the video processing, not anything in a layer. 

Any ideas as to what might be happening here?