Thanks for the input.

A couple more details, the first of which is flat out embarrassing:
It wasn't color negative film. The film came back from the lab positive. The shot that hit me as having the color cast was shot late in the day...approximately 30 minutes before sunset. Unsurprisingly, it had a harsh yellow/orange color cast. I didn't shoot any exposures with a flash.

Thanks for the detailed input 2F/2F. I'll have to re-read it a couple of times before it penetrates my 1" thick skull though