I have not measured my Operator, but let me take a stab at this. I used to have an M3 on mine, and it also moved back and forth. It's not an issue for functionality, just a slight annoyance. That bar is made to fit on both Glock rails and Picatinny rails. The Glock rail has a narrower slot. I have a Surefire X200A on my Operator now, and it comes with a lock bar for Picatinny rails and one for Glocks. They are indeed different in width.
The Operator is a Picatinny. Anyway, I don't know if Insight Technologies makes a truly wide enough bar for the Picatinny rails, but like I said, it's just an annoyance, and not a functionality issue. Once you shoot the gun, the light moves forward, and pretty much stays there. You might try and sight it in with the light pushed forward and see if it affect POI using the laser compared to when the sight is moved back in the slot.