It seems that only when playing against the computer this situation appears. A sequence leading to it starts with: 1. f7 f8 2.g7. And then black moves something. White tries to go g8 and now white has the option of capturing en passant at g7. This should not happen.
I've been using the diagram here: https://www.chessvariants.com/index/listcomments.php?itemid=1200173ceb826d24&order=DESC.
It seems that only when playing against the computer this situation appears. A sequence leading to it starts with: 1. f7 f8 2.g7. And then black moves something. White tries to go g8 and now white has the option of capturing en passant at g7. This should not happen.