The left bar end is often loose on the stock bars, it's held in there by rubber grommets that expand and grab the bar from the inside when the phillips bolt at the end is tightened. Don't yank it out. I tightened mine by loosening the bolt pulling and spinning until the guts came out and lathered it in loctite and putting back in. Much better now.
One of the rearsets also sticks out further than the other when looking from the rear.
All part of the charm of the 919.
The stock bars from my 05 are the same as the factory manual shows.
There is a wee hole that a sprung retaining tang on the inner weight is supposed to engage.
This is what is supposed to preclude the inner from coming out.
If that tang has been bent down, or broken off, or not been located such that it can find the hole in the handlebar, then the inner is subject to moving out.
If the inner is properly located and retained, it should never come out.
As for the outer weight, I found one side tended to loosen more than the other, and my quick fix was a dab of silicone seal on the threads of the mounting screw - worked like a charm.
Meanwhile, the LSLs I use on the Renthal ULs I have had on for years, work like a charm and stay on without any extra help.