Putting together a stag lower with the PSA MOE ACT LPK http://palmettostatearmory.com/palmetto-state-armory-moe-act-lpk.html

The safety, won't switch back to "safe" from "fire".  It moves fine without the detent and spring in, and moves fine from "safe" to "fire".  I'll take a picture tonight.  

Anyone experience this?

If the hammer is upright in the lower, the safety will not move to safe - this is by design.   Once the hammer is cocked, it should allow the safety to move to "safe".    

I understand that.

This is with the hammer down.  

It's either the groove on the safety or the detent is getting hung up in some manner inside the lower.  

Edit: I'll make a short video of it tonight.

No need, it is either the detent, the spring, or the safety itself.    IM sent.

I have to say I am impressed with how committed you guys are to customer service.  

Believe it or not... I actually find the cheap MIM safety levers (ebay) have better "feel" (cleaner snap from positions) than the US "mil spec" offerings. I buy a bunch of those cheapies to replace the crap ones that come with LPK's. Other than that... lube the selector detent liberally, make sure you're running good springs (also ebay.. you can find 20 packs of Colt springs, which is what I use), and swap selectors if need be.
I find that selector "feel" is NEVER consistent with LPK's (or even when switching grips.. which all vary minimally with selector spring depth). I used to clip coils to get the exact "feel" I like, but have stopped doing that, as the springs settle down after time (and become easier anyway). You'll have to play around with different combo's to get the stiffness you want (but keep in mind... they WILL loosen over time, so don't go for "perfect" at the get go or you'll wind up with a soft selector later).

I received the replacement pieces.  Installed. Works as it should.

Thank you PSA.