Google has said that the Google Search Console rich results report for product structured data now provides more granular levels of errors. Google said starting September 29th, “Search Console now provides more granularity in error reporting for Product structured data items.”
Because Google has changes the errors it may show in this report, you may see your products rich result report look a bit different from the historical data, prior to September 29, 2021. Google said “as a result, many issues involving incorrect formatting that were formerly marked as invalid object are now marked more specifically with invalid type or format categories.”
You should see an annotation on the report on September 28th or 29th I believe, here is a screenshot from a random Search Console profile I have access to with this report:
You can see the annotation on the right that when you hover over it, it says “An event has occurred in Google Search that might affect your site’s data.”
So you may see more useful and helpful errors in this report to help you debug product structured data going forward.
Forum discussion at Twitter.