So, we have an 11.5" SOLGW barrel (carbine gas) mated to an Aero upper.
Lower is a Spikes
Strike Industries bolt catch (I wanted the larger paddles)
H2 carbine buffer
Springco White (standard) carbine spring.
Brand new PMags
5.56 55gr. ammo (brass case) from Patriot Defense.

With one round in the mag, the bolt catch catches the BCG on empty - every time I tried it.
With two or more rounds, it usually does not hold the bolt open (occasionally does).
If I hold the bolt catch down on the last round, the bolt locks back.
Manual charge on empty mag locks the bolt back.
Ejection pattern is tough to gauge in the indoor range, but the brass seems to bounce off the divider at 3:00.

Initially, I suspected I had used the wrong spring in the bolt catch. It was the first spring I installed, and the last one came up short (buffer retainer spring).  After getting a new spring and roll pin (and better punches), I was dismayed to find the spring was correct. With a new spring and unmangled roll pin installed, I went to the range again today, and the same exact behavior.  I can't really fathom why it would lock back after one round, but not two, 5, or ten. I'm gonna spend some time tonight looking at the bolt catch engagement with some empty mags, but any thoughts on what I should look at next? H3 buffer to slow things down? New bolt catch? Might the H2 be a bit too heavy?

Edited to add ammo info.

Can you compare the tension on the bolt catch from the spring with that of another AR?  

I had a similar problem and it turned out there was actually a burr inside the bolt catch spring pocket that was keeping the spring from seating all the way and putting excessive tension on the bolt catch.

Thank you for your reply.
I do not have another immediately available to compare. It doesn't feel much different from the M4's I used to handle often when I was active duty. Though, granted those had the standard bolt catch with less surface area to press on. I may just remove the catch again and try to inspect the pocket. Maybe put in a standard catch while I'm at it.

Strike industries bolt catch did not work on a forged lower build. It does seem to work on an another standard mill spec lower that I put it on.

After swapping to a different gas block (with set screws on my dimpled barrel), it now runs 100%. I ran mag after mag of 3, 4 and 5 rounds; and it locked back every time.  It would seem that perhaps I had a small misalignment of the previous gas block (clamp).