I'm using Adobe Indesign 16.2.1 on a MacBook Pro (13-inch, M1, 2020). macOS Big Sur 1.3.1.
I've never ran into this issue before, even on the M1 laptop. When I export my file as a PDF (interactive or print), the first page doesn't show the color blocks. It's only on the first page, screenshot attached. It does show the colors through Apple preview but not through Adobe Acrobat DC version 21.0.