You have a point maybe this is the reason why he did not name the gambling site, he needs to double check if possible ask a friend who knows how to code so he can check the accuracy of his report, if it's true that the site is showing differently, then he can strike a deal or go here to post accusations with all the proof.
This is what happens very often, so i think this is real reason. I faced it to many times on online hashing sites, so to verify yourself you need something like Python, hashlib and right command like
hashlib.sha256(b"neededseed").hexdigestThen he can share his conclusions here