It probably analyzed that taking the queen leaves black in a worse position. Black is losing a bishop anyway, It's not a blunder. You should find the best move to whatever the computer answer is, in this case - taking the f7 bishop.
There's analysis feature provided right inside the puzzles. If you're struggling to understand, use it and all your questions will be answered. Trust me, all of those "blunders" are yours, not computer's.