Perhaps you got an older version ?
On mine the pill is immovable and fitted from behind, so the shelf will always be correctly aligned inside the head.
If you had the old standard C8 pill design, screwing in from the front, then tightening it up could have loosened the reflector fit. If so, you could shim it out. On mine, everything is snug. Not possible to assemble it incorrectly.
If you look at this review, Thorfire C8s review and teardown dated Wed, 07/15/2015 it is a completely different torch to mine.
Almost everything has changed. The reflector (his has two distinct grooves machined into it), the pill (completely different, and the thermal compound shows that it was not exactly flat, nor conducting the heat properly), the head is redesigned for the new rear-fitting pill, the driver PCB is quite different, the driver mode order (it now ramps up, not down), the springs, the tail switch PCB, the switch itself and the spacer for the tailcap rubber. Even the weight (mine is 151 grams).
Every difference from mine suggests attention to detail, and continuous improvement.
That’s why I am so keen to see the next version. I wonder what they could have further improved ?
Update: I was wrong about the pill, it does unscrew out of the front. I’ve updated my original post.