Well. Exact reason is still a mystry to me as well ! Initially when I was testing I was not able to perform rate limiting at all and just a lucky hit this happened. Usually it should not happen, even never saw before/after this particular case. Just a lucky hit I would say. ☺

One thing that they were not using traditional recaptcha/hcaptcha, etc. It was one of their own captcha setup.

Btw, thank you for going through each of blogs and raising queries, it will help others too. Appreciate it and I hope I would be able to respond well.

The program do not have option to pull coordinate disclosure, else would have disclosed the video PoC happily.