What is the computer analysis trying to pull?

So I played a game and won by resignation.  I sent in for the analysis of the game.  Looking at the last "play might have continued" line I see, well it looks like to me, that the analysis set my opponent up for a nice mate on me.  Doesn't the analysis have ~2500 rating?  How could this happen?  Has this happened to anyone else?

Yes.

Yes, and thats pretty funny:)

wow... how about that... i guess its just not meant to see more than that many moves no mater what level its programed at

yes this happends a lot, it looks for a lower depth and stops, it would see the mate if it looks 1 more move into the variation.

22...Rd1#

Are you sure the computer didn't play 21. Rcxc7, instead of Rdxc7?

Chess.com computer analysis, it turns out, is unusually weak. I have a class example of this as well. See the following game. Move list shows Chess.Com engine (CCE) responding with exd5 which is very weak: