So I tried this tactic on the app.
https://www.chess.com/puzzles/problem/667934
I played Qc5, and the computer tried to play the pinned rook Rdd1, which obviously didn't work, there was the illegal move buzz and then my time kept ticking but all my pieces were locked since I guess white hasn't made a legal move.
On desktop the computer played Rad1.
This might be connected to the bug where the wrong piece is moved when premoving sometimes when two of the same pieces can move to that square, it sometimes flips a coin which one to move rather than playing the move you actually played.
There are also several other problems with the app (android). First of all, when you solve a puzzle (or fail to) it doesn't show the par time, rating, puzzle number etc.
Then when I wanted to record it and play it again, I couldn't if I go to statistics and click on this specific puzzle, it just gives the default starting position but shows that the last moves played were Rd4, Qc5.
Also sharing the puzzle, it shares a link, clicking it opens it in the browser, rather than the app. The app should catch chess.com URLs and ask if you want to open it with the app or the browser.
Another big problem with the mobile version is when you fail or just retry, you need to scroll the screen down and the tooltip appears for the hint button, except it's fixed to the screen position rather than the button and when you scroll back up to see the board the annoying tooltip covers it with no way to remove it.