So I figured out the problem.  I was using a different oven (much larger) the oven had two large fans meant to distribute the heat.  The fans were stuck due to ungreased bearings.  The part did not get to the usual cure temperature.  When I rebaked the part, I did not bake it long enough.  

how old was the prepreg when you bought it? and how much has it been sat outside at room temp?

All parameters were the same. What worked last time under the exact same conditions did not work this time.  The only difference was time about 4 mos since the last build   What is perplexing, is old prepreg will cure. This was perfectly workable but just will not cure. 

Was your last cure also with an aluminium mould?

I am using a layer of the surface carbon with 2 layers of 400 gsm prepreg. I used the same material from the same role successfully in the past at the same temperature and cure time. 150f and 200 f. I use an aluminum mold under constant vacuum. The only change in procedure has been time since last used (about 4 months). The carbon is probably 8 months old or so, and has been frozen when not used. The carbon failed to cure. It is quite bizarre.