So since last patch tracking weps has been really weird, random shots will just completely ignore your target and go off into the side. Its happening with almost all weps, ive noticed it on thorax weps and burst, not sure if its a visual bug or if the shots are actually just going all over the place for no apparent reason.

It's a visual bug. If you notice, when the other projectiles hit the target the bugged projectile also dissapears.