I have been running nightfalls each week trying to get a rake angle, however since i have all the nightfalls weapons they should all have an even drop chance. But every week i have run multiple nightfalls, i always get the same 2 weapons (cruel mercy and the swarm). About 1 in 5 runs i will get a different weapon but from what i've been getting it seams as the 3rd "random" weapon is on a weekly rotation. I don't think getting the same 2 weapons every week is bad rng and it is extremely annoying getting the same 2 weapons when it's meant to be an even drop chance after you acquire all nightfall weapons.