If you look closely you'll see one of the A's legs on that part of the "rune" perhaps it was meant to be that way. Almost like it could be coruppting it.

The real mistake is actually this, the writing at the bottom of the poster and all concept art, ect has War of Magiv when translated, I guess thats okay since I'm the only one who noticed so far, lol

Would that be the same missing yellow that's also missing from the "Elemental" at the top of all the web pages?

Makes one wonder if it's intentional or not, since the trailing foot of the "A" overlaps, it might not be missing so much as covered (at least on the web logo, haven't looked at the poster).