I prefer BWP-recaptcha than WP-recaptcha. But WP-recaptcha is another option and is not old, just another posible choice.
Anyway I don't know if it is a good idea to refuse to investigate what was wrong because I'm not very sure it was a problem with BWP-recaptcha and maybe WP-recaptcha is just ignoring those kind of errors that BWP-recaptcha does not ignore and catch.
That kind of error probably appears when their is a problem of communication between the web server where the site is hosted and google recaptcha api server when trying to validate recaptchas. Maybe it was even just a temporal problem in your web server.
But well, I don't know. I just mark this as resolved as we can't know why you get that error.