The schema.org validator and Google’s Rich Results Test are not the same thing. Schema.org just checks if your markup is structurally valid, Google’s tool checks if it qualifies for a rich result which has stricter requirements.
First thing I’d change is switching from microdata to JSON-LD. Google technically supports both but FAQ schema in microdata format has always been patchy with Google’s parser. JSON-LD is far more reliable and easier to debug.
Second and this is the bigger issue nobody mentioned, Google rolled back FAQ rich results for most websites in August 2023. They now only show FAQ rich results for government and health websites. So even if your schema is perfectly valid, the rich result simply won’t appear in search for a regular ecommerce store regardless of how clean the markup is.
Your schema showing up in the Rich Results Test doesn’t guarantee it’ll actually show in search anymore. Google made that change quietly and a lot of people still don’t know about it.
What FAQ schema still does is help Google understand your page content better, which has indirect SEO value, and it does still show in AI search tools like Perplexity and Google’s AI Overviews. So it’s still worth having, just don’t expect the accordion dropdowns in regular search results anymore.
If you want to verify the JSON-LD route still works structurally, convert your microdata to JSON-LD and retest. The markup itself is fine, it’s Google’s eligibility criteria that’s the wall here.