Hmmm...interesting. I never had this problem before until just recently on my SP map that I'm doing now in which I am having the exact problem with one of my evacs...
However, I haven't double checked it with my first time doing this trigger in an MP map. I know I have done it successfully in I think my Mutation Triad map. That map can be found at PPM by going
Here(notice PPMs new main page layout anyone

also just for Aro and TB congrats on finally getting your spotlights at PPM...I'm sure that has something to do with you guys talking to banshee or Muldrake though

)