I've had similiar experiences with Cyclopeeze and LPS.My Faviids will readily take CE but my Mussids and Euphyliids will not.Funny thing is,my Euphyllia spp. wont accept mysis either yet my Branching Hammer has proven to be the fastest growing stoney coral i've kept.I assume its eating some of the other foods when i broadcast feed the tank because in 2.5yrs,it has never accepted a direct feeding..
BTW,I use mysis as a staple for all my LPS corals.