Recently purchased the S&W M&P15T

Product: Model M&P15T - 5.56 mm, Tactical

And I noticed that right out of the box, the tactical quad rail (which is bolted to the D ring) can laterally twist a slight amount. I can twist the D ring/rail, but only to the point where the gas tube (which runs through the D ring) stops it from rotating more. It throws off the front sight which is attached to the rail. Is this normal?

I somewhat remedied the issue by attaching a low profile riser to bridge the gap between the rail on the upper receiver and the quad rail.

ARR-378 - AR-15 .5" High 5.7" Long 13 Slot Low Profile Riser Mount UTG Leapers Picatinny Rail Quick Detach Riser Mount

Is the D ring loose? Is it normal? Thanks for any input.