Google Webmaster Trends Analyst John Mueller wrote a detailed post on Google+ explaining how the Search Console reporting works and why it may seem delayed for some of the reports.
The short answer is that it takes time for the data to get to the Search Console because of (a) the time it takes Google to send the data from the crawling department to the search console department and (b) the fact that different URLs on a site can be crawled less or more frequently.
Here is how John Mueller put it, so it is crystal clear:
When it comes to the aggregated reports in Search Console, there are two time-elements involved that are good to be aware of:
- Latency from crawling to reporting. It takes a few days (to about a week) for Search Console to display data after it’s been crawled. There are various processes that run over the data, and Search Console tries to reflect the final state — which can take a bit of time to get. This is particularly visible with an abrupt change, such as going from “no AMP pages” to “lots of AMP pages.”
- Per-URL crawl rates differ. Some URLs are crawled every few minutes, others just every couple months, and many somewhere in between. If you go from “all URLs are broken” to “all URLs are fixed” (which is awesome if you have a way to do that!), it will take some time to drop to “zero errors” in the aggregated reports. This is probably too much, but I created a simple spreadsheet to show that, feel free to make a copy & play with it: https://goo.gl/1pToL8
If Google doesn’t show my site’s AMP errors or hasn’t picked up that we fixed some of our crawl errors yesterday, it’s simply because of time delays in crawl and report delivery.
Many webmasters already know that the Google Search Console data is delayed by two days or more; this explains why that is the case.