Never mind the chowdered ends, one flute is wider than the other.
I've never seen anything like that before.
Rummaging through the box of goodies that came with my mill.
I assume they are for aluminum?
It's ground like that, so it acts as an wiper from the one longer end cut. Rather it works that way or no, I don't know. I've seen a few of them in my past, not a popular grind. Easy to fix if you know someone who is set up to regrind endmills. Not something you want to fix by hand.
What Timmeh said, it's so they can plunge into the work without a pilot hole when slotting, fish them back out of the trash!
The centre doesn't cut brilliantly because SFM drops to zero on the axis, a bit like drill bits, but the ability to plunge cut without a pilot hole speeds jobs up and makes 'em worth having.
I found a few of those in some dull endmills that I was given. Discovered them when I was sharpening endmills. They sharped easy enough, but you can not "correct the grind" as someone suggested as the helix is off center. The sharpened ones seem to cut ok.