Troy TRX BattleRail Alignment Issue

[ThePunisher]

I have build two AR's with Troy TRX Extreme Battle handguards, and I just finished a third. However, on this build, once I installed the barrel nut and then installed the forend, I have a small problem. You are supposed to install the forend slightly to the left of the receiver, and then twist it clockwise so that it snaps into place. There is a little tab that prevents the forend from going to far...however, when the little tab hits the upper, the rail is offset a little to the right of the receiver. If I line up the receiver and the forend and tighten the bolts it is fine, but it sometimes shifts a little. Any thoughts on this? I cut up a piece of crush washer and put it between the upper and the little tab, however I am hoping there is a better looking solution. The upper is a key hole forging, so I don't think it is an issue...