Why are you commenting and gaslighting on these threads in the bug report forum?
Kindly stop, let the devs do their job and don’t tell others there is no issue when you have no proof of the matter. Do you also write to people who had a game crash and say no, “the game didn’t crash, you’re seeing things?”
We all know that there are indeed bugs in the game and there is code that is related to mythic drops (spark on the first kill) that is currently not working as intended.
It is possible that there are further bugs related to this that affect the mythic drop rates for certain players in certain circumstances.
By the way, with your example stats of 1.5% chance with 5 items per kill makes my argument even more compelling. I then have 1.5% x 2000 loot rolls with 0 mythics.
Then after running the lower torments, I received 8 mythics in the next 2000 loot rolls.
I have no evidence if running lower torments did something or not, however using simple statistics and probability calculations it is highly unlikely that these results would occur if there is no relationship. Only the development team will have enough data to truly test or know if the drop rates are working as expected over a large enough sample size. However, I assume that it is uncommon for people to totally skip T1 and move to T4 for kills, so if there is any issue it will be harder to diagnose.