Update 3/29: I have found the source of the problem. It is in the original Sunspot Theme. 🙁 I built my child theme using it. I am looking to see if I can find the problem. That requires digging through the code that runs that theme.
If I cannot find the problem or an easy fix, I’ll be changing the theme, which is a tedious process as I have several modifications that support the pages for various brands of viewers.