[utmostvanilla]

I used to work on these sort of games and one would play a few rounds to get a feel that everything was working correctly and to see things like the transition to win states etc. Obviously, we wouldn’t be spending our own real money to do this: we would be playing against a dev server that produced the results. I find it hard to believe there would be zero QA before launch so I can only assume there was a mismatch between the dev and release versions of the backend.

[JoshuaDavid]

I wouldn't be surprised if it was something like, on the dev server

    SLOT_GAME_WIN_FRACTION=0.95

and then

    $win_fraction = (float) getenv('SLOT_GAME_WIN_FRACTION');

and then nobody bothered to set the environment variable on prod.