Sanford, are you saying that when someone is referred to a munchkin tracked web page that uses HTTPS from a Google search where they are logged in to Google (URL's scheme is ), that the Referrer URL will be captured?
Yes, https: -> https: will be captured, AFAIK (let us say, there is no standard prohibition against it as there is with https: -> http:)
Note, however, that this is the true referrer we're talking about. Google bounces you off their base domain first so the referrer doesn't have the query string -- but that is nonetheless the real referring site. Yahoo will show the full thing.1
ETA: 1 Meaning a network trace of Yahoo traffic shows Y doesn't "massage" the referrer via an interstitial page before JS-redirecting to your site. Instead they use an HTTP redirect (Google will do the same thing if you have JavaScript disabled, I think). All standard rules (and possibly non-standard browser implementations) apply from there.
To return to @Ravi Ansal's question, the bottom line is there are conditions that Marketo can't workaround where the capital-R Referrer (as in the document.referrer property) isn't available or is truncated so that it isn't as actionable as you want. Unless you can establish that the full document.referrer is available to JavaScript and yet isn't associated with the web action, I don't think you've found a bug.
ETA: Hope it's cool that I'm editing my Correct Answer, but actually the above remark about Yahoo not using an interstitial is wrong, per research I posted later. Both Google and Yahoo (as of this writing) use interstitial ping pages which change their ostensibly secure search to only partially secure. Other search engines like Bing maintain better security from end to end. Please read my later comments here for the bigger picture.