I think I found the problem:
Your template's style.css sets for "h1.componentheading" the value "position: relative".
So you need to add some custom css to fix the problem with the JEM componentheadings. Insert the following code to a css file. The best would be, if you have a custom css file, otherwise you can use the jem.css file but that will be overritten in the next update.
Code:
div#jem h1.componentheading {
position: unset !important;
}
This css code changes only the behavior of JEMs componentheadings and touches not the other componentheadings.
Thanks to your previous work (two lines / same line) it was easy to find. Good teamwork!