If you found bug really and have enough proofs tell admin about it. If they get it clearly a bug they might solve it and you will be rewarded I guess. Cause freebitco isn't a scam or cheat website. There is actually one thing problematic and that is 5% house edge.
I don't know if it's a bug or it was made on purpose to reward only member who deposit (it's just my guess uh)
I thought the site was completely fair too, but i can't explain those 2 different hashes in no other ways
It's better to wait the answer of an admin from freebitcoin