Ensure the JavaScript behavior is executed only once per page

I hoped this would be a simple revision of the JavaScript behavior making use of Drupal core's once library, but that doesn't seem to solve the issue. Now instead of always getting 5 iframes, sometimes I get none, and sometimes I get 5. Will keep digging.

Turns out the library itself being included multiple times per page was the issue. I went ahead and converted all three JS libraries to remove jQuery and add Drupal's once to prevent multiple application of the behaviors. All works great now!