The YouTube Monetization staff has been the single most inconsistent thing on YouTube, and that's saying a lot nowadays, with all the crazy changes the site has undergone in the last few months.
Direct partners have had problems with varying requirements for proof of permission to use my music, and it seems that some of them go to the extremes of requiring image or pdf formats of license or permission documents. With the advent of "affiliate" partners, I can only assume that this problem will get worse.
In order to finally satisfy the monitization staff of YouTube, I've replaced the former permission form on my website with a form that will create a PDF document specifically giving permission to the information you enter in the form, which is also time-stamped.
Thank you for your patience. I will now resume writing and producing music.