When you use this test, note that many ad tracking pixels/scripts (even Google's pixels and Doubleclick's pixels (Google owns Doubleclick)) may be blocked by their own robots.txt file that you cannot control. I've seen this first hand in one of my own sites -- Google blocked their own Doubleclick pixel from being scanned by the Googlebot. You have to ask yourself, "The Googlebot is for identifying content on your page, not following pixel trackers. Even Google's own tracking pixels are blocking its own Googlebot. So, why should I care if it's the pixel trackers being blocked?" And I see this also with Facebook's pixel, too.
However, if it's a robots.txt file that you control, and doesn't have anything to do with pixel tracking, then it's likely something that you need to address. Now, if you have a membership-only portion of your website, or an admin-only portion of your website, and it is linked from the homepage, then you might consider link-cloaking or nofollow link attributes so that the Googlebot doesn't try to follow that in your page. However, one has to ask if Google wants you to allow the Googlebot past a member- or admin-only section of your website, which is likely no in my opinion.
This is my opinion, however. Unless we can actually get Google's SEO Engineering Team to respond, we're kind of groping in the dark and just have to use our best common sense intuition here.