Did the computer just cheat?

I was sitting here playing chess.com's chess app on my phone and the computer just tripped me out. I played it on 1 minute strength (the highest setting). I'm white. Here is the move sequence: 1. e4 d5 2. exd5 Qxd5 3. Nf3 Bg4 4. Be2 Bxf3 5. gxf3 e5 6. Nc3 Qd7 7. Bb5 c6 8. Ba4 0-0-0.

Now if you know what you're looking at you'll know the computer castled without moving it's knight on b8. Is this a specialized rule only the computer knows or did I just get cheated by a computer?

I've emailed myself the game. I don't know what use that'll do.

I've looked everywhere I can think to look to find a reference to this particular maneuver but, I've been unable to find any. I'm specifically hoping someone can do one of the following, recreate the moves and conditions to get the same/different outcome, explain why this happened, or make me look like an idiot by telling me this is a totally legit move.

I tried making a diagram of what happened but it won't let me recreate the final 0-0-0.  

Some chess computers have poor castling rules built into them. for example there might only be a flag that mentions king hasnt moved, rook hasnt moved, no check currently or on any in between square, and the squares moved into must be empty, and they missed that nothing must be in the way.

^Very Likely. My bet is that there is a bug that disregards the b8 square during O-O-O.

As seen above it is clearly an illegal move. Castling is not allowed when there are pieces between the rook and king.

Thanks for your responses.  

lol looks to me like the chess computer just pulled a level of badass.