Yea, the only thing that I see that could cause problem with this code is in the seed that is chosen (a bad seed can ruin the best rand code). Also, how it is chosen(for example, if the rand-seed is reset at each start of the game and is chosen in a selection you could have the same pattern of shuffle repeated over and over again).
(I don’t say it’s the case, and I am sure it’s, like AMM said, only a psychological/luck thing)