[JimMorrison]

OMG I just wrote one of my typically long replies - and my mouse mysteriously went to the Post Reply button above, instead of the much stealthier Post Quick Reply button below. And of course, it ate the post.

To sum up my thinking - my best guess is that there is some sort of artificial "need to move" script involved with giving a unit Quickness. The act of casting a spell is supposed to override Quickness, so scripting to use the magic items bypasses that "need to move". Best I can come up with.