Hi,
i have an issue with "Komento 2.0.9" running on "Joomla 3.6" (seamed to be also an issue on Joomla! 3.5.1 as far as I could see in my local demo environment). When a user is trying to post a comment (Visitor or Guest) then he got the error "Invalid reCAPTCHA response". I tried the fix mentioned
here but that didn´t solved the issue. It only shows then "Captcha required". To troubleshoot that issue I currently use the Beez3 template in my test environment, so you should be able to reproduce the issue.
Keep noted that I use Komento on localhost, so I couldn´t share my website. But if useful i could setup a temp. demo System.