While RNG is RNG, and while everything points to the percentages being correct when tested against a large number of checks, there does seem to be something odd with the RNG used.

"Streaks" with multiple failures or successes in a row seem to be more common than they should be. While some streaks of bad luck or good luck are inevitable with any good RNG, they do seem to be longer and more common than should be expected from a perfect RNG. Since streaks of bad luck seem just as common as those of good luck it all appears to average out in the end, so it is not clear if this is to be considered a bug or not.

Someone better at statistics than me would be needed to verify if the impression of streaks of good/bad luck happening to often is correct or not.