Why is this move considered a BLUNDER?

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MrMarshMan
Played as black. Move 16 for black where black Bishop captures white Rook on square e2 is flagged as BLUNDER by Lichess computer analysis. I thought it was a good exchange, but it seems like I overlooked some vulnerability. Can anyone help me in finding what am I missing?
 
 
 
justbefair
MrMarshMan

I still didn't understand. Can you elucidate it a bit further?