UGH I knew it! The brand is "Gourmet Rodent;" they (were) really reliable, up 'till now. I'll see if I can get rats somewhere else for a little while, and see if they can win back my loyalty.
Do all ball pythons avert from bloody rats?
The feeders PetSMART and PetCo sell suck. I loathe them. I've had issues with both Artic Mice and Gourmet Rodent products, up to and including feeders that were allowed to decompose before they were frozen.

I've had the occasional rat-with-bloody-nose but it happens less and less now that I have a really great local feeder supplier.