Problem with Bootstrap Studio 4 using Bootstrap 3 website

I just installed Bootstrap Studio 4.02.

There is a problem with viewing websites made with Bootstrap 3. When using the RESPONSIVE VISIBILITY, anything hidden with hidden-sm or hidden-lg is not hidden in the view with Bootstrap Studio 4.02.

When viewed online, it's correct.

Not sure what could be causing this. It works when I test it. Is this for a standard Bootstrap 3 design, or one that is converted to 4?

For a standard Bootstrap 3 website.

Hmm, I loaded up a couple things I did a while back that I didn't convert to BS4 and I'm able to toggle those options on/off without any issue in the app myself.