Weird "noise" in AI map file that doesn't show up in PDF form

Hi all,

I'm making maps in AI, and I've found what I can only describe as "noise" in the AI files, but when I save the maps as PDFs, the noise disappears. Basically it's like ghost versions of text, elevation colors, and that kind of thing lurking in the background. I've attached a screenshot showing both file types. Does anyone know what could be going on? I use Windows 10 and a Lenovo laptop, in case that matters. The fonts are all pretty small -- 5 or 6 point light Callibri. Thanks in advance!