Today I made a test : Install only jDownloads v3.2.42 (latest version) and Komento Pro 2.0.6 (latest version) on Joomla 3.5.1 (latest version) , with PHP 7.0.4 . No any other 3rd party extensions.
Then I set integration with jDownloads on Komento Pro settings.
Next, I created new downloads, and a new menu item for jDownloads. Then I checked the frontend page.
Well, Komento Pro can show commenting form on the file details page, but, there are two (double) commenting forms on the same page!
Apparently this is a bug of Komento Pro.
Hope you will fix it soon.
Thank you.