Chris, I had this same problem again last night with a pair of your cards. I noticed that while trying to troubleshoot, if I moved the wire a certain way, both mics worked great. So I removed the mic cover and tried readjusting that plastic grounding sleeve and replaced cap and still on one channel working.
I then tried this same method with mics plugged in and got good signal than when I replaced jack cover, lost same channel signal. Removed jack cover again and noticed that when I moved wires around soldering area that both channels worked great and then would lose one signal when I attempted to replace cap.
Next time I did the same thing and just did my recording without replacing the jack cover.
I had called you on 8.11 or 8.12, when I opened my package to test my mics and had this same problem. That was when you told me about the capsule tab check and the plastic sleeve check, which is what seemed to solve the problem.
I have had this problem a few times and still can not use PM so sorry about going about this publicly, but I know it will get taken care of one way or another.
Gabriel