I did a build and after one shooting trip noticed the hand guard was loose enough when torqued down to  rotate around the YHM barrel nut with not much force.  As I was looking I noticed it's notched out on the lower to mate with the lower, but doesn't.  My BCM's do mate with upper to prevent rotating and help to align the rails.  Anyone else have this problem?  If so, what's the fix?  For the mean time I machined down the piece of the guard the captures and locks it onto the nut to make it less prone to move,  But I can't imagine this should be necessary with a $200 guard!  YHM's warranty is pretty clear on returns, and I plan on calling them this week.  I have a red dot on this rifle, so not a huge deal except that now my BUIS's are not reliable.

I'm pretty bummed on YHM for this issue.....

Any ideas, or similar issues?

Pictures?