Animator changes scale of object for no reason

I have a set of sprites that I am animating to make them flash - so I just alpha them from 1.0 to 0.0 and back, in a loop. For some reason, when I use the SetTrigger command to start their animations, their scale gets changed.

In editor they look fine, but when I deploy to an iPad HD, they look tiny because their scale is fixed, and not resolution dependent.

I have other objects that I do the same thing to, with a different animation clip, and it works fine.

I tried deleting the animation and recreating it from scratch, and it still happens.

Has anyone had this happen? Any ideas on how to resolve it?