Google AdSense Earnings Drop With HTTPS Migrations

So I was all excited migrating over this site to SSL and my corporate site but despite very little ranking changes, both negative or positive thus far, AdSense earnings seem to have taken a hit somewhat.

Yes, Google AdSense is supported on HTTPS / SSL / Secure web sites but not all the inventory seems to be available, resulting in lower earnings for those who migrate.

An AdSense publisher back in March made the switch to HTTPS and then had to switch back to HTTP after noticing the earnings drop was too much. He posted about it in the Google AdSense Help forums back then and no word from a Google representative as to why. Pete Claar @pclaar said:

AdSense ads have reset to much lower paying ads. RPM are dramatically lower to what they were before the switch. I'm assuming that this is because the https site is a totally new site to Google -- and the trust I've built in the http site is lost on the https one.

He then asked for advice on "the best way for me to proceed" but no response from Google.

Some publishers claim to have dropped 35% in earnings after the HTTPS migration. I decided to look at my AdSense reports, which I rarely ever do, since I monetize my sites mostly without AdSense, although there are some AdSense units on both this site (one unit on this site) and a few random ones on article pages on Rusty Brick.

The average RPM (page revenue per thousand impressions) before on this site was $1.27. Then after the migration, which was only about seven days, dropped to $0.47. Although, yesterday was a good day, with $1.61 RPM on that day alone, if you count it.

Here are the revenue charts for both sites, earnings directly, and keep in mind, this site has news spikes, so ad revenue from AdSense is hard to measure by pure revenue, so looking at RPM is a better measure.

 Meanwhile, something must be wrong with my corporate site because $0 since the migration:

Did you notice a similar trend when migrating to HTTPS?

Forum discussion at Google AdSense Help.

Update: Well, as pointed out in the comments below, this is no secret, Google's documentation says this also:

HTTPS-enabled sites require that all content on the page, including the ads, be SSL-compliant. As such, AdSense will remove all non-SSL compliant ads from competing in the auction on these pages. If you do decide to convert your HTTP site to HTTPS, please be aware that because we remove non-SSL compliant ads from the auction, thereby reducing auction pressure, ads on your HTTPS pages might earn less than those on your HTTP pages.