Why are there many impossible medium difficulty problems randomly generated
This is intended. If you have played the challenge in the original game, this should be pretty straightforward and easy to understand.
If you have not yet played the original game: Impossible puzzles are only generated in the "select 1 in 3" parts where there are 3 horizontally aligned puzzles with similar elements, but only one of them is solvable and you need to find which one is solvable and solve it to proceed.
