Cheating software.
The industry is not doing itself any favours over this. There have been numerous allegations by players who have had terrible runs and post that "the ****** game at **** is clearly rigged". These have been hard to prove, and the majority opinion is that it was just a run of bad luck and the games in gereral are fair. Operators have replied by saying how robust their software is, how well their RNG has been designed and tested to produce fair results.
Now, the conspiracy theorists have caught not one, but TWO casinos out cheating! In both instances, it was NOTHING to do with the fairness of the RNG, it was all to do with how the software converts that random number into a set of cards, dice, or reels for the game the player is playing.
The can of worms is now well and truly open. Many are feeling that online Blackjack simply does not "feel right" on occasion, and I am one of them, having said that sometimes I can play seemingly forever and all the luck is bad with no spells of good luck as might be expected to balance out the runs. I have conceded that the RNG itself must be as near to random as makes no difference, and have surmised that there must be some kind of algorithm that makes the game more "interesting" by implementing some kind of bias feedback to keep streaks going more one way than another, and that this bias changes slowly, hence advice from some casinos to leave the game alone and come back next week, strangely, it seems to work!
I would be interested to know what process they use to convert numbers to things like cards in Blackjack, a subtle error here can make all the difference, and if slight may never come to light.
I believe the PWC verification looks at the number of times cards appear and conclude that all cards appear with the frequency they should, what it does NOT look at is whether bias exists that causes the hand as a whole to be continually good or bad for either player or dealer, such as sequencing the cards in such a way that a player always gets the bust card and the dealer gets the run of low cards to make the proverbial silk purse of the Sow's ear hand started with! ( I have a particular gripe with the runs of eternal pushes of my good hands against an initial crap up card for the dealer, followed by always busting when it is I that have the "challenging" hard 14!