Google has confirmed that some may see a spike in unparsable structured data errors within Google Search Console. This spike should be ignored if it happened between January 13 and 16th of this year. Google said "This was due to an internal misconfiguration that will be fixed soon, and can be ignored."
This report is relatively new, it was added in May 2019. The Unparsable Structured Data report aggregates parsing issues such as structured data syntax errors that prevented Google from identifying the feature type. Google said "that is the reason these issues are aggregated here instead of the intended specific feature report." You can use this report to see if Google was unable to parse any of the structured data you tried to add to your site. You can access this report directly over here.
Here is what it looks like:
Again, if you see a spike between January 13th and January 16th, Google is aware.
Forum discussion at Twitter.
