Google posted on the data anomalies page that Google Search Console AMP error reporting starting today, December 10th, will become more generic in nature. Specifically Google said “AMP enhancement report will now combine some over-specific issue types into fewer generalized issue types.”
So Google is going to give you less specific detailed errors here and keep the errors more generic overall. Google wrote:
The AMP enhancement report will now combine some over-specific issue types into fewer generalized issue types. When the migration is complete, you will see an increase in generic issue types with a corresponding decrease in the specific issue types that were combined into the general type. As an example, the following two issues would be combined as shown.
For example, old specific issues that were for (a) The attribute ‘title’ in tag ‘a’ is set to ‘cat’, which is incorrect or (b) The attribute ‘title’ in tag ‘a’ is set to ‘dog’, which is incorrect would be grouped into this single generic error “The attribute ‘title’ in tag ‘a’ is incorrect.”
Google said this is to help you make these errors “more manageable.” Google wrote:
This will simplify issue types into more manageable groups for you. You should see very little overall change in your instance count. During migration you will not be able to verify issues as fixed in Search Console.
Google also said they will update the previous three months of data (starting in September) to conform to this new system.
Forum discussion at Twitter.