It might be a symptom of another issue altogether, such as Firefox blocking some assets or communication. I noticed that I can pass most instances of reCAPTCHA

It might be a symptom of another issue altogether, such as Firefox blocking some assets or communication. I noticed that I can pass most instances of reCAPTCHA by randomly moving my cursor across the page for 2-3 seconds before clicking on the checkbox. Usually this lets me bypass the image captcha portion, assuming the reCAPTCHA was not configured for additional security. This probably works on invisible reCAPTCHA as well.