Google has announced that Google AdSense is now supported on HTTPS sites without any issue.
If you want the new support system to work, go to your AdSense console, click on existing ad units, and you will get the revised code. The new or revised code will work on HTTP and HTTPS websites.
AdSense Software Engineer, Sandor Sas said,
"HTTPS-enabled sites require that all content on the page, including the ads, be SSL-compliant. As a result, our systems will remove all non-SSL compliant ads from competing in the auction on these pages. This means that if you convert your HTTP site to HTTPS, ads on your HTTPS pages might earn less than those on your HTTP pages".
You can visit the Help Center of Google AdSense to get more details about the feature.HTTPS Websites Now Support Google AdSense!,