Googlebot continues to crawl mp4 files in the format www.example.com/video/12345.mp4?md5=2029zanlkdain312on&expires=1523327783 which has obviously expired (only valid timestamp+30minutes, after which 410 response is given), and causes a crawl anomaly on the parent html url. Some of the timestamps we are seeing are almost 2 years in the past. Strange thing is that google uses a regular useragent ("Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Googlebot/2.1; +http://www.google.com/bot.html) and not Googlebot-video (Googlebot-Video/1.0). Our sitemap contains direct video urls without md5 and expires parameters as we only allow rdns googlebot verified hosts to fetch our videos without secure_link, and those videos are downloaded fully with Googlebot-video useragent.
We are trying to get rid of these crawl anomalies and have our pages re-indexed.