For me, it was the ignitor (the hardest part to replace!) Unfortunately, I wouldn't say your issue is DEFINITELY the ignitor, but you should be able to tell by swapping left/right, bulbs first, then ballasts, finally ignitors. One of those swaps should move the problem to the other side of the car, and you'll have your culprit.
The same logic can be used for the discoloring. I'm guessing it's the bulb itself, but maybe the ballast or ignitor is doing something funky to it.