My E2DL does the same thing, and I sent it into SF. I got a new head, new tailcap, and the problem remains the same. I got a knowledgeable rep on the phone, and he said that the same thing happens to his. He talked with the engineers, and it is simply the way it is.
It looks like they should have put in some sort of minimum delay for switching modes ... for example, if the light is off for less than .1 seconds, don't switch modes. Maybe that's not possible, but it should be :).