The same thing happened to me! I answered correctly, got a congrats and then hit get started and it vanished. I can’t find a trace of it and almost thought I was crazy. There’s no email with any details either.
Looks like they are all different. I just now got my offer and completed it and it was only $7. Some people have to complete 41 or 42 offers and then someone only had to complete 16. Very rando