Captivate Web Objects - PDF file problem

Using macOS High Sierra Version 10.13.5 on a Mac Pro (2013) with Adobe Captivate 10.0.1.285, and also tested on a Windows 10 Pro version 1709 OS: 16299.547 with Adobe Captivate 2019.

Having a weird little problem that I'm wondering if anyone has suggestions for. In Captivate, I have a project with several PDF's that I've loaded into a web server and then I'm inserting the link as a web address in a web object. The PDFs look great in preview until I try to apply an action to it. If it's hidden upon entering the slide and I use a button to reveal it, the PDF is now zoomed way out. I have to click the zoom button within the web object to view it. This doesn't happen in Internet Explorer on my PC, but it happens in Safari and Chrome on my mac and in chrome on the PC.

If I uncheck autoload then use a button to reveal the hidden web object (then click to load the PDF), the PDF files look okay and are the proper size, but I'd prefer that they autoload.

Any ideas? Any more info needed?