Interesting. Never seen that before. Someone else wil chime in.
Good Day captq, 
This happened to my MH20 when it was delivered & I tried it with a flat top Samsung 30Q battery (as an "experiment").
I knew that they need a Button Top battery, therefore the result surprised me. After a few cycles on/off it stopped working with the Flat Top battery.
Are you using a Button Top battery?
What batteries are they?
Best Regards,
George
I just got one myself. If you carry it with the head up, the pocket clip is fixed (can’t rotate).
-Jamie M.
I initially planned to reply with ‘you are a genius’… but, and perhaps I’m alone in this with a faulty MH20, it seems turning the clip upside-down and carrying it with the head up results in the clip becoming slightly looser. to me, this is unacceptable (especially considering I was already on the fence with the detachable clip in the first place). further, I would indeed prefer to carry it with the head pointed down as I sometimes use it to illuminate the ground without unclipping.
the best solution I’ve come up with so far is a steel ring to hold the clip still (using the stock keychain hole).
I also had trouble with the stock clip catching on my kuhl (nylon/denim?) pants due to the ~2mm gap so 3D printed a little ramp.
i used the head from one of those mini-bungees for the steel ring. (rest of photos incl. video of me smacking clip against table)
!
!
Knock-off ? :
ONE THOUSAND NUMENS !
Compared against my Zebralight sc600w ii L2 the lowest light level on the MH20 is WAY too bright. Need to be half or maybe a third of its brightness 
-Jamie M.