The best workaround that I just came up with is this:
Overlay an invisible button on top of the entire interactive container field, that prevents the user from clicking inside the container field. If they try to click on the invisible button, it does something else (anything I want). However, if they just HOVER over the button and scroll up & down, then they can still scroll the container field.
A very old trick for allowing a user access to the data in a field without allowing them to modify the data is to define a calculation field that copies the value of the data field and then put that calculation field on the layout.
Haven't tried it with an interactive container field, but I suspect that it might work for this...
Ooh, great thinking, Phil! I've used that since I was a toddler for text fields, number fields, date fields, etc... but I've never tried it for an interactive container field! I will try right now and let you know if it works!
Thanks, Phil. That did the trick! On iOS, it even has the added bonus of automatically showing a pop-up action menu with a "View" option to zoom into the PDF. But thankfully, it hides all the other options (delete, replace, etc.) because it is a calculation field.