The discoloration is on the ceramic that's OUTSIDE of the engine/combustion chamber, beginning at the base (nearest threads) but only creeping up a couple millimeters. Enough to notice, only discolored - no particles.

 

It's fairly normal as long as they all about the same.

 

About 1,000 miles, the "miss" is less frequent upon startup now, no code has returned yet. YET. Not holding my breath - just wanted to give an update!

 

Chin up! Keep enjoying the ride, and thanks for the update