Are there any other techs that can only target enemies "in-range"?
Also, the specific situation was: on the 600AD scene on Zenan bridge, in the fight with the four skeleton enemies (name escapes me), only one was "in-range" for Fire Zone. I selected and confirmed the attack at the same time as that same skeleton attacked Crono (who was wearing a Wrath Band), so Crono's (lethal) counterattack came before the tech and since there was no longer a target, the attack "failed". I'd guess that the animation was probably left in as a fallback for any situation where a tech somehow tried to target an enemy that wasn't there and couldn't choose another, to prevent crashing.