Bob, you beat me to making the post. I did call him late today to try and find out what was true. As he just posted, that is incorrect information about the high mode being used repeatedly causing increased pressure and risking damage to the bulb. He also denied it causing any significant erosion of the electrode contact points, nor is it to prevent overheating as Ra mentioned.
Again, he made it clear that this was only to comply with military requests that the user not get visually acclimated to always seeing the bright mode which is not necessary for most functions, and so the battery would last longer as a result.
He said the normal mode runs at 50W, High mode is 75W, and that these bulbs can run at surprisingly higher watts. Again, he said there is no risk to the bulb if it is run on high continuously.
The inference to Larry's "Exploded Bulb" thesis is that it was related to some other dirt/oil issue. I would personally add that no manufacturing process is 100%, so even a possible bad bulb, or shipping/drop damage could be suspect.
The main point is if something like this comes up, go to the source for a real answer. Thanks Bob!
PS) This is a magnificent light!
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