Google's Gary Illyes posted a PSA on Twitter saying if your crawl rate changed after switching your site over to a CDN, that you should let them know about it.
Here is the tweet:
If you switch to a cdn and your crawl rate drops, contact the googlebot team via the form in the crawl rate feature pic.twitter.com/cah8GpxxEL
— Gary Illyes (@methode) June 13, 2016
With that, he also shared a photo of a Wallaby.
He said send the feedback via the crawl rate feature, which is under the gears/setting icon when you are in a property within the Google Search Console.
Forum discussion at Twitter.
Update: Use this form to contact Google.