Posed this question to one of my vendor reps today. Somewhat discussed as a concept in lamp manuals but not pictured in any troubleshooting guides. These are HMI 1200w/GS lamps showing more build up on one side than the other and more wear on the opposing side. I see this once in a while with other lamps. What's the cause of it? Is this ok, non-important or something to be concerned about?