Computers can be very bad due to software / hardware handicaps.
Chess.com auto analyze your games in what? 1-2 minutes? That's a joke. Engines are free. Download stockfish and an interface like arena or scid if you're actually interested. As far as I'm concerned browser analysis on chess.com, lichess, et al is a gimmick. I never use that stuff except to find some extremely forcing tactic I might have missed.
@eupoth the engine should NOT be formulating bad moves in its alternative variations. I have had the exact same things happen to me. I have notified support and sent them evidence of what the new engine is doing. I suggest you take screenshots of the variations the analysis engine is formulating and a screenshot of where it shows its own moves re evaluated as a blunder or mistake and send these to customer support. This will help them fix what is happening with the new engine. In my case that I have reported the analysis engine gave me a new "best" move for my blunder and a list of moves past this point 10 moves deep. When I played this variation in the analysis section the engine found 4 blunders in its own list of suggested moves!! All those moves in its suggested line variation should be "best" moves and there should not be innacuracies, mistakes and blunders in it. Take screenshots and report to the support team like I have done. They need to see evidence of what the new engine is doing wrong.
Let's say I'm using the Game Report to analyze a game I just finished. The computer finds a blunder that was played, and suggests an alternate move. Hovering over the alternate move with my cursor, I see a small thumbnail image of what the board would look like, and then I click, which brings me to an analysis sub-window where I can play out the game as it would have continued had I made that move.
This gives me the option to click the "play" button and see the moves play out on the board, as I watch. However, the computer doesn't show me the best moves. It shows me a continuation of the game comprised mostly of mistakes and inaccuracies. Although I suppose it could be educative to examine those erroneous lines, I don't understand why the computer is choosing bad moves (you can also see the "best" move at the upper-right of the window, but the computer still goes with the mistake.)
To be clear, these mistakes are not ones that were played in the game by an live opponent. These are potential mistakes that the computer seems to be finding as alternatives to the best move, and then it chooses to make the mistake or inaccuracy. My only theory is that the computer is attempting to emulate the level of play that someone with my, and my opponent's, rating would have potentially made. I honestly can't think of much usefulness for this, and I would prefer to see the best moves being played out.
Can anyone shed some light onto why this may be happening and if there is a setting to change this behavior? Thanks in advance for the info.