Any AT&T 3G MicroCell users out there? I've got a big problem

As regular listeners of the Verge Mobile Show know, my home is effectively a Faraday cage, so I'm stuck using boosters or femtocells regardless of carrier. I use a 3G MicroCell from AT&T, mostly paired to an iPhone 5 currently.

In the past 2-3 months, I've developed this problem where the person on the other end of the call reports that I'm breaking up, usually within five minutes of the start of the call. It never resolves itself — I need to hang up and call back. On my end, I continue to hear the other person just fine. It basically renders my phone useless (as a phone, anyway).

Originally, I had the MicroCell connected to my router, which isn't the recommended configuration — AT&T wants you to connect it directly to your modem and connect the router to the MicroCell, so that your voice packets can get top priority. I did that, no change. I've tried restarting the MicroCell over and over again, doesn't have any effect. I'm on a 105Mbps Comcast connection that seems to work fine with extremely low latency, so I'm hesitant to point the finger at that.

Anyone else have a similar experience? Is it fixable? AT&T's had MicroCell problems before: when it first launched, there was just enough voice delay on calls to make holding a conversation a huge challenge. It resolved itself over time, presumably through firmware updates (which happen silently and without notification) or changes on AT&T's end. I'm hopeful this is the same, but the MicroCell is just enough of a niche product — a product that's never advertised — that I don't know how many eyes AT&T engineers really have on it.