Evade me no longer

For some reason, the first evade bug moment I remember happened in Zul'Farrak. We were clearing the basilisk pulls before attempting Antu'sul (why is it that the optional bosses always have a couple of sweet warrior drops?) and the mage in the group wanted to skip the whole thing. Impatient, he decided to start nuking away from atop one of the hills surrounding the area and managed to pull aggro, but the basilisk couldn't path up to him (and to be honest I'm not sure how he got up there) and promptly went evade. He wouldn't come down because he rightly knew the mob would hit him, and so it took us a solid ten minutes of arguing before he finally came into the monster's reach so that I could taunt it.

I'm thinking about this because of the Isle of Quel'Danas dailies, specifically the quest Crush the Dawnblade. For some reason whenever I do this quest I run into Dawnblade Summoners who are evading. This puzzles me because I can't understand why a ranged mob is evading: it doesn't have to path to anything to hit it, just get into range. Is there some way a hunter or some other ranged class can shoot them but stay out of their range?

All I know is, they stay evading for what seems to be forever. There always seems to be one or two hanging out around the Bloodcrystal, impervious to attack, and another couple scattered around the island. Once I found one evade bugging merrily out by the coast, surrounded by imps. I suppose this could just be how they relax.

This may have just made me more sensitive to evades in general, since I seem to have had a week full of them: evades in TK, evades in ZA (the multiple lynx packs evaded twice, that was fun) and a fantastic evade on a Gruul's pug where Kiggler just couldn't or wouldn't hit the moonkin. The lynx packs evading doesn't even make sense, as the mage was right there spamming AoE and they should have had no difficulty pathing to him. Heck, nobody else seemed to have trouble heading over to hit him in the head, what was the problem for the cats, distracted by a momentary gigantic ball of yarn?

Have you noticed any further evade oddities lately? Mobs that seem to get stuck a lot, or particular instances that seem prone to the issue?