Scrollbar missing in new UX on custom screens

Hi!

We have experienced 3 customers with custom screens where the scrollbar is missing after they got the new UX. Is this a bug? 

We know how to fix it, but is this something that should be fixed in the system?

We need to add this;

<style>
  #HtmlPage_rightDiv {
    overflow: scroll !important;
  }
</style>