I still don’t know whether you’re supposed to hit those and I also don’t know if it’s normal to get two challenges or if that just means I did the first one wrong.
It has to be more sophisticated than that. Otherwise users could easily taint the datasets by giving wrong answers on purpose.
It probably checks your answer against the current model’s best guess and if it’s close enough, you get a pass and your input is added to the training data for the next iteration. The more wrong you are, the more challenges you get.
...Then you select it, and the Captcha fails. (telegra.ph)