Interesting reading here
Under No CAPTCHA reCAPTCHA
reCAPTCHA has become nearly impossible to complete for people who frequently clear their cookies.Supposebly by 2017 this no longer occured or shouldnt
Under security
You can have 32 tries at captcha before it will lock you out
https://en.wikipedia.org/wiki/ReCAPT...TCHA_reCAPTCHA
Software engineer Andrew Munsell, in his article "Captchas Are Becoming Ridiculous" states "A couple of years ago, I don’t remember being truly baffled by a captcha. In fact, reCAPTCHA was one of the better systems I’d seen. It wasn’t difficult to solve, and it seemed to work when I used it on my own websites." Munsell goes on to state, after encountering a series of unintelligible images that despite refreshing "Again, and again, and again. The captchas were not only difficult for a computer to read, but impossible for a human." Munsell then provided numerous examples.
https://en.wikipedia.org/wiki/ReCAPTCHA#Criticism
https://en.wikipedia.org/wiki/ReCAPTCHA