A Google Webmaster Help thread has a webmaster who has deployed App Indexing and is upset because the content mismatch report within the Google Search Console seems to have stopped producing data.
Supposedly, the data has not updated since September 9th. The webmaster said, "Note that "Last crawl date" in the bottom right corner is 9th of September."
Here is his chart:
John Mueller said he believes that the team is reworking that data. John said:
Thanks for posting -- it's good to hear of more sites using App-Indexing! The team is currently looking into this, to see what we can do there; I believe they're currently revamping this data. In the meantime, one neat thing you can now do is to use Fetch as Google on an APK that you upload just for this purpose, which should make it a bit easier to double-check the issues that you're aware of.
Have you had issues with your App Indexing reports in the Google Search Console? Keep in mind, this is brand new stuff for Google.
Forum discussion at Google Webmaster Help.