Seriously. I have jack of all trades, I am PROFFICIEN IN FREAKING PERFORMANCE and ...
Just for the record ... these two things exclude each other, you know that right? O_o
You either get your profficiency (and expertise, if you have it) ...
OR
You get Jack of All Trades ... so you have "at least" some bonus to your roll.
But never both.
I feel like I'm missing something, why would weight dice make it more likely to get 5 2's in a row?
That's a good question. Makes me wonder what's going on under the hood, so to speak.
I didnt check under the hood for this ...
But if i remember it corectly, weighted dice should incerase your chance that you will get more "regular" rolls ... meaning less 1's and 20's, and more +/- around 10's in general.
My personal guess (but ONLY guess, based on nothing) would be that the game runs some stream that is for pre-dephined amount of time checking your rolls ... starting once you roll 1 or 20 ... and if during that time it rolls 1 or 20 again, it will re-roll it so you get more "middle" result ...
Keep in mind that actual rolling takes the system fragment of second ... that animation is there just for effect.