As much as it's fun to argue a point in order to convince yourself you're right, at some point you have to concede that the people who write the code make mistakes.

I'm perfectly willing to accept that Blizzard hasn't coded it properly or it has some strange bugs.

But I also don't think a couple examples posted to reddit qualifies as a valid data set.

I don't have a degree in math, but I still know not to draw conclusions based on a data set of a couple reddit posts. Whenever it happens, it'll get reported. A single legendary drop doesn't get reported at all.

just accept it's a bug that inflates the values.

How could I accept that? Blizzard said they fixed it, so I'll assume they did unless they say otherwise. They have the data, we don't.

You'd need a lot of data to see if there's a problem. Base drop chance, how it changes based on content, how that increases with failed loots, when people get their legendaries and after how many tries.

This is the only way to actually see whether drop rates are different from the intended implementation. And only Blizzard has that data.