PDF dropdown lists aren't visible in markup
I created a PDF in Acrobat that contains text fields, check boxes and drop-down lists, as well as blank space. I'm trying to fill it out on my ipad by opening it in files and have also tried to do it by importing it into the Books app. In both cases, the drop-down lists don't display and I can't make a choice. Is there a way to fix this? The check boxes and text fields work fine, and I can add content in the blank space using pencil.
iPad Mini 5, iPadOS 14