Puzzle number #508232 is WRONG!! The 'solution' involves an illegal move

I know I know, another patzer who is unable to solve the puzzle cries that its the puzzle that is wrong. No this puzzle really is wrong. This is a screenshot of the puzzle as I got when doing tactics. The 'solution' is Kg3 Kg1 Rg2 check Kh1 Rg4 discovered check Kh2 (as pictured below) -

However this is where the puzzle fails, because the 'solution' is Rxb4 !! How is it possible to do Rxb4 when the c4 pawn is in the way? WTF kind of a solution is that? Here is the computer even suggesting Rxb4 as the solution.

So I moved Rxb4 and Viola the move happened !! The rook transformed into a knight and jumped on the c4 pawn and captured the enemy rook. I was shocked!! Here is proof -

As you see the white rook has successfully captured the black rook on b4 from the g4 box, even though the c4 pawn was in the way, and such a capture is illegal. What is more the illegal move 'solved' the tactic! This needs to be fixed

There's no pawn on c4 when I open the puzzle

https://www.chess.com/tactics/508232

Weird, it was there when I did it. Its there in the screenshot.