I did a quick test agains AI1 with this
and I got this
I'll let you do the math, but at least 10 times out of 30 the mulligan happend and i never draw a pillar in the first 14 cards (2 full hands). coincidence?
Firstly, I'm not sure how you know when the mulligan was activated as it is "invisible". One
can determine when the mulligan was activated AND failed because you'll have an opening hand with no 0-cost cards. Also, I count 11 instances of your first QP being beyond the 14th card. The math regarding drawing BOTH QP's in the opening 7 cards is 0.0483 + (0.5861 * 0.0830) = 9.69%. This lines up as 0.0969 * 30 = 2.91 expected instances compared to the 3 you experienced. A-OK there!
The math also says that with a 30-card deck containing 2 zero-cost cards the probability of not drawing a QP in opening hand is the probability of no QP in the initial opening hand multiplied by the probability of drawing no QP on the mulligan hand (when not drawing a QP in the initial opening hand):
(1 - 0.4139) * (1 - 0.5257) = 0.2780, or 27.8% of the draws with such a deck will yield you an opening hand without a QP. 0.278 * 30 = 8.34 expected instances of no QP the opening hand in 30 game sample size.
Now, to go another 7 turns without drawing one of the (2) QP's in the deck is another iteration of the "mulligan process" - that of 2 successes in 23 size population with sample size of 7.
0.2780 * (1 - 0.5257) = 0.1319, or 13.2% of your games with such a 2 zero-cost 30-card deck will leave you QP-less 14 cards into the deck. 0.1319 * 30 = 3.957 expected instances of no QP in the first 14 cards in a 30 game sample size. Your experience shows NO instances of drawing a QP outside your opening hand BUT within the next 7 cards - very strange indeed. Also, the 11 games without QP in the first 14 cards is more than expected and the ELEVEN without a AP in the first 14 cards is much higher than the expected. None of this shocks me as the sample size of 30 games is quite small for values this sensitive to sample size.
More experimentation is required to get us all to the bottom of this!