horde bug?

in the Horde, a white pawn on the first rank can move two squares. BUT, if black has a pawn on the sixth rank, and white moves his first rank pawn two squares and passes the capture square, black can NOT capture en passant in the Horde at lichess. Is that a programming bug? I would think black should be able to capture en passant

I have never played Horde, but this behavior is intentional and mentioned on https://lichess.org/variant/horde:

However, Pawns of the Pieces may not capture Pawns on the first rank that have moved two squares as it is not a valid en passant capture.