URGENT: N-Light ST50 XM-L owners. Bright flash when changing to LO mode...normal??

I recently purchased a N-Light ST50 XM-L NW version and when clicking the rather stiff forward clickie to change modes, the light would emit a really bright flash when changing modes from HI to LO. I emailed the seller and he says that N-Light confirms that its "normal" due to the design of their driver. The seller is happy for me to return the light for a refund.

Here comes the best part, being a CPF member, I guess I do not like to be taken for a ride. So here I am posting this question to the owners and experts of LED flashlights: Is it normal for multimode XM-L drivers to exhibit a bright flash when changing modes from HI to LO?

If not, does this sound like a manufacturing/design fault to you? I have googled this issue and found nothing that would explain this bright flashing to be "normal".

Thank you for your answers.

My unit didn't have this behaviour:

Youtube clip from my review (in spanish), here: http://reviewsdelinternas.blogspot.com.es/2012/10/n-light-st50.html

As you can see from the video, there is a brief flash when changing modes from HI to LO. Take a close look at the reflections against the black flashlight holster just above hotspot to get a better view of the flash just before it comes on LO.