We have been experiencing the same thing with the V2. For such a simple tool, it fails ALL the time. We are averaging around 10% fail rate right now. As an admin of the site, I experience the issue all the time where my answers fail. It can happen 10x in a row and then the 11th it works. My concern is my lack of understanding of the "no-recaptcha" metric. From what we've seen, if I paired that with the failed, it would probably be pretty close to the number of issues we are seeing daily (i'm hoping that's not the case).
I've read through this forum quite a bit and have seen TONS of posts saying the same thing but no one from Google is responding. As a company this is very frustrating since my platform is configured to use Google reCaptcha and to move to something else would be a lot of effort.