It looks like there was a bug in our comment permissions that was causing an issue adding comments to cards without the *update permission. I fixed and patched it. Now that you have a sign-in account, it shouldn't bother you any more anyway. I apologize for the frustration!
Support Ticket
Can't add comment with captcha+issues
Captchas on your how-to video page never recognize my (correct) attempts
It looks like there was a bug in our comment permissions that was causing an issue adding comments to cards without the *update permission. I fixed and patched it. Now that you have a sign-in account, it shouldn't bother you any more anyway. I apologize for the frustration!