Screen-sharing with audio in breakout rooms

I teach a class over Zoom and we frequently split into breakout rooms. During these group sessions I sometimes ask that one student share their screen in order to view presentations together, usually videos. In some cases the other students are not able to hear the audio, the way they are when I share my screen in the main room. I imagine it has to do with a setting on their end, but I can't figure out what that might be. None of them had headphones connected. 

I am wondering if there is a setting I can change as host to make this work better or if it is something on their individual Zoom or device settings