Hey Pyro,
Just wanted to let you know that my truncata X Vetchie has shown me some yellow before, as has my ventricosa X Maxima, and my Merrilliana... when I increased the lighting by adding new bulbs a couple of weeks ago, something fun happend, all those yellow spots have begun blushing, and some have a really intese RED coloration to them now! (Note, this is not burning, this is coloration coming out) many leaves are showing the blush of better light making them more red, but these yellow spots I think just show it better.
I was worried when this happens, as yellow leaves in normal plants mean they need what is it.. I forget, potassium? but I just kept on trucking, I have one leaf that went totally yeallow, but is handily keeping my larges pitcher alive...
ANd my growth on all the nepenthes is larger, and darker with the new light, the truncata x vetchie seems to appreciate it as well!