[fungalreason]

It's a problem with any ranged unit that has flying, I think. (I learned not leave boots of flying on mages with bows in another game).

What I think happens is: whenever a range unit determines that it's out of range of something it attempts to move forward until something is in range. If they fly, they move immediately to the front lines and get engaged in melee. Since the Zmey have a short range to begin with, it's rare that they'll have something to shoot at on the first turn of the battle. I haven't specifically tested it with them, but I'm guessing they just fly to the front and use normal attacks if you set them to "fire closest"?