This problem with the CARM loop last night was the fault of a bug that I had put into the LSC model last week.  When I gave the input matrix and normalization matrix double rows, I had put the goto tags for the CARM normalization matrix rows backwards.  So, even though I thought I was not normalizing CARM, in fact I was normalizing by POPDC, which was near zero since the PRM was misaligned.

Anyhow, found, fixed, currently locking, and all seems well.