Bootstrap -Videos in Pane won't stop playing when switching to another pane

Hi,
I encountered a strange issue with my bootstrap layout. I have used a lot of YouTube videos as part of my teaching materials.Whenever I have a video playing under a pane and without finishing or stopping the video, I tried switching to another pane, the video from the previous pane would not stop automatically thus I could still hear the audio.
However, playing video in a page automatically stops when I switched to another page which is the normal behavior of my page.
My Bootstrap website has a layout below.


Thank you for looking into this.