Gary Illyes from Google has confirmed on Twitter that the index status report within the Google Search console is "broken right now." So Google is aware of the issues but the index status count may not be accurate for you.
Here are the sets of tweets that show the dialog:
@Ryosuke_Shiga Yeah, it's broken right now, we know about it. We asked the team to take a look. Sorry about that— Gary Illyes (@methode) August 22, 2016
So to get a better count of indexed pages, use your Sitemap report first. Although, hopefully the index status report will be corrected soon.
I do not see any mention of this issue on the data anomalies page.
Forum discussion at Twitter.