Wrong Loadout/Guns switiching automatically

I don’t have too many problems with Halo thus far. But the one thing that really annoys me is when I choose one load out, say with my DMR/Magnum, and then I’ll die and all of a sudden it’s a different loadout with a BR/boltshot. But when I go to change the load out again, it shows that I am using the one I originally picked… Also, I was playing a game on complex, and I got a Beam Rifle in my ordinance. I was carrying DMR/Beam rifle. I used the beam rifle, switched to my DMR because it overheated, but it was a BR. I switched back to the beam rifle, and back again, and it was my DMR again. I’ve also had a few games where I’ll be shooting someone, and all of a sudden my pistol is out and I’m dead. Anyone else having any other problems like these?