The theme I am using currently is editorial 2.0.
Lately, I’ve been getting lots of issues with Google’s AMP. The common problem seems to occur from the !important CSS qualifier not allowed issue.
After proofreading all pages with the problem, I realized almost all of them contained a bullet list or numbered list.
The line above a bullet list or numbered list will always have the problem of owning multiple headings. I don’t know how to fix this, except to prevent the use of bullet list in the first place. However, it comes at an expense of limiting the number of ways I can present my article.
I don’t know if this is just a recent update or an issue for a long time, but Google has stopped indexing me for these minor formatting problems.