The Google Search Console has added a new type of error to the markup report structured data. About it reported
on the Data Anomalies page.
Now Google logs as an error those cases when the URL is specified in the field where the text value is expected. This applies to markup implemented using RDF or microdata.
According to the company, the most common cases are pages with incorrect tagging using itemprop. It is expected that the text content of the tag will be used. then when in fact is the href value.
The correct implementation in this case will use nested tag inside tag where stands for non-url value.
Google began to highlight these errors on December 3.