Playing vs Computer my pawns are being captured illegally

Ill see if i can get it to happen again and take a picture, but my pawns(only in human vs computer) are being captured as if they were one square higher on the file instead of the actual position. Even in the analysis of a game vs. the computer it recommended a move based on a line that involved taking a pawn illegally. I'm not complaining, it's not a big deal i just thought it was bizarre.

It's legal. It's called an "en passant" capture.

You should review the rules of chess.

https://www.chess.com/learn-how-to-play-chess

aaaaah memories.... my dad introduced me to this by checkmating me with his pawn like that.

Thank you very much for taking the time to explain this bizarre rule to me. I'm a beginner but i thought i had a decent grasp on the rules of the game. I was very confused but you did a fantastic job explaining the concept to me in a way i could easily understand.

I'm still a little curious as to why it's a rule, but knowing how it works is certainly good enough for now. 

Pawns used to only be able to move one square on any move. One change made to speed up the games, was the optional two step move. Without the option of capturing en passant, it would be possible to completely lock up positions by moving past a pawn on it's fifth rank. 

Thank you, that actually makes sense to me! I appreciate the response, this is great community full of very nice people.