Indexed pages dashboard: New or old, which is correct?

Question

There is a discrepancy between the data in my "Index" dashboard in the new search console versus the old one and I am not sure which I should believe.

Plausibly of more concern, the old one shows a significant drop in indexed pages. Though I cannot place why this would have happened, if this is true, it is evidently of high priority to figure out why.

I do not necessarily see a ridiculous drop in observations, although growth is slower than expected.

Images: First picture shows the old dashboard with a drop around the 4th of April (to roughly 37,000 pages) and the second shows the new dashboard with hardly any change. The high number of index errors is expected (forcefull "noindex"). The low ratio of index/discovered not, though this has been for months.

Answer 1

In the Search Console beta, I'm not sure if "valid" pages means that those are your indexed pages. If you look at the first chart you'll see that you've had more indexed pages than considered valid in the second chart.

Deindexing of pages does happen. Google may have once considered a site to be worth indexing and sending traffic to, and then later on changed its mind for a variety of reasons. It's quite possible that you have lost indexing and if there's anything you can do about it in terms of improving your site or fixing penalties you should try to do so.

I would trust the index status of the current Search Console instead of the data seen in beta if there are any discrepancies.