I had this great idea about printing the image out of LR to a file so I could show everyone what the "bad" profile looked like, and guess what? The file looked fine. It was only messed up when I actually printed the image. So I checked and, you guessed it, 100% clogged PK nozzle. Mystery solved.
Sigh. Sometimes it's the simple stuff that bites you.
I'd just like to add an important information. Sometimes when I leave the printer off for some days, specially in those periods of low humidity (afternoons of 30% or less), even when nozzle tests show everything 100% ok, it's possible to see some color cast. Fortunately, a single cleaning cycle is enough to recover the profiled color balance.