Is “overflow: scroll” still the proper way to do this?

I am testing out some new plugin options for an upcoming site and have been using “overflow: scroll” on 2 of my websites, but when I had the plugin author look at an unrelated issue he told me the overflow scroll bar wasn’t even showing and that the fabric box just cut off at 350px with no scroll bar. Can someone tell me if there’s something more universal that I am supposed to be using for this instead of overflow: scroll?

Test spots you can see them on, in the attributes section with the fabrics…
https://www.outdoorwickerstore.com/product/wicker-sofa-island-collection/
https://www.outdoordrapesandcurtains.com/product/curtains-with-loops-50×84/

Thanks!!