Bug - PAWN move on wrong place

Hello,

I am just in the middle of play with my friend, and have strange problems with wrong move of pawn. Please see attached screen, which shows analysis of our game. Please note:

screen 1 - white pawn moves to b4

screen 2 - I click on my black pawn, and see posibility to move it from c4 to b3 (sic!)

screen 3 - after movin to b3 - white pawn from b4 (!) is removed from the game

Is it something wrong with my chess knowledge? Or did I find bug? :)

FYI - screens are from analysis of the game, but same move possibility can be seen on regular game.

Best Regards

Thank you firefly2611, can you imagine how could I search for that move not knowing "en passent" ?

Great, thank you all for help.

Best Regards

thats an en pasent