Engine Misses Mate in Two Despite Finding Another Mate in Two Plus Other Mates

In the following position I played 21...Ree4, with unstoppable checkmate on the next move:

Yet the Chess.com Stockfish 15 engine at depth 20 missed it, despite finding another mate in two plus other checkmates.  Check out the screenshot below:

And just to prove 21...Ree4 leads to checkmate on the next move the following screenshot now shows the proper evaluation of mate next move afterwards:

So clearly 21...Ree4 is not a check and the three checkmates suggested by the engine in the first screenshot begin with check so I would have to assume this is why the engine originally missed 21...Ree4.  However I am genuinely surprised that the engine would have missed 21...Ree4 when it found another mate in two and other checkmates.  I literally did not think engines would be capable of missing such a checkmate under these circumstances.

I have seen the engine miss checkmates before in composed problems but I am not sure if I have ever seen one this short missed in a composition, let alone a real game position.

That is weird indeed.

Agreed!

Thanks for bumping!