MArcomage

I played Pegasus and got Blood shrine.
Then I played Militia and chose to discard that Blood shrine.
It wasn't discarded. Probably I got the same card, but my
pile of discarded cards was empty.

Can you please provide a game replay?

The game is not finished yet.

This does sound like what would happen if the drawn card were another Blood shrine. The system wouldn't produce a discard pile because it doesn't "see" a change to that card position. I would have guessed that drawing another of the same would be disallowed, though.

Mojko wrote:
Can you please provide a game replay?

http://arcomage.net/?location=Replays_details&CurrentReplay=383710&PlayerView=1&Turn=35

Ah, so Blood shrine was already a New card during that round immediately before its discard (which you did explain in your first post). I'm guessing that's why the system didn't notice. It does look like it was discarded and, though the odds are pretty low, randomly drawn as the card that replaced itself.

It is indeed the situation as DPsycho described, however it is possible to fix this. Individual cards can be set to never redraw the same card as they discarded.