Its from the little color brouchure that comes with the '06 manual.

"...The hybrid high voltage battery may go through a self-reconditioning process from time-to-time, to optimize high voltage battery performance. You may notice slight changes in drivability during the reconditioning process. This is an imporant part of the Escape Hybrid's high voltage battery optimizing features..."

I can't tell you if thats what its doing... but sometimes I wonder if when people say "my engine isn't shutting down 'normally'" if this isn't exactly whats happening and they might just relax and let it go about and do its thing.

Clearly its sometimes A/C and heat realted... but perhaps not always.