About cancelling a skill (Otyugh, Virus): This isn´t a bug. As soon as you klick on the card, the card is activated and used, and all costs are paid (Like quanta, or the death of the virus card). Even by canceling the ability, the cost is already paid and you won´t get it back. Anyway, that´s intended.
About the randomness: It´s random.
Card drawing: At the start of each game, if you don´t have any no-quanta-cost card in your hand, and Auto-Mulligan activates, which lets you redraw your cards. (Only once per game) Aside from that, it´s completely random. That´s why there is the possibility that you get several pillars and no creatures while drawing five cards. The opposite is also possible. Why? Cause it´s random.
Quanta Pillars: You can get an equal amount of quanta of each element. You might not get the quanta you need and everything else, and you can get exactly the quanta you need, with nothing else. Everything is possible. Why? Because it´s random.
There is only one thing randomness doesn´t know: Even distibution. Mathematically it won´t happen often that everything is evenly distibuted. Why? Because it´s random.
