On December 28, 2021, Google updated the rich results report for product structured data in Google Search Console. The reporting update may result in a change in the number of issues, errors and warnings that you get on and after December 28th in that report.
Google posted this update in the data anomalies page saying "Search Console has changed the way that it evaluates and reports errors in Product structured data. As a result, you may see changes in the number of Product entities and issues reported for your property, as well as a change in severity of some issues from errors to warnings."
So if you use product structured data, go check that rich results report. There may be new issues and errors that you probably want to address in your next sprint or two.
Using Product structured data? -> Google Search Console products rich result report error handling updated on 12/28
— Glenn Gabe (@glenngabe) December 31, 2021
"You may see changes in the # of Product entities & issues reported for your property, as well as a change in severity..." https://t.co/KrJwazGlJw via @rustybrick pic.twitter.com/IjffSiDTmu
Forum discussion at Twitter.