Google posted in the data anomalies page that the crawl stats report deep inside the Google Search Console interface had internal reporting issue between March 10 and March 23, 2021. As a result of the data issues, you may see a "drop in data in this period," Google said.
The data in the reporting is just a data bug and Google said there was no issue with your site's performance in Google Search as it is related to the data in Search Console. "This issue did not affect actual page fetches, only the reporting of fetch activity during this period," Google explained.
So just a heads up if you see a dip in the crawl stats between March 10th and March 23rd, this is a known data bug in Google Search Console.
Forum discussion at Twitter.
Glenn Gabe found one with a huge drop:
I didn't see any drop for a number of properties... and then I saw this. Wow, glad Google explained it's just a reporting issue. Would have raised red flags for sure :) -> Google Crawl Stats Report Internal Data Issues March 10-23, 2021 https://t.co/7eyamh1Yk1 via @rustybrick pic.twitter.com/U3Kb6aZ73t
— Glenn Gabe (@glenngabe) March 25, 2021