Stressing acans will keep them deflated for a few days in most cases. Usually when I pick up lords, epoxy the bottom of the frag plug and stick it somewhere new in the tank, they are totally flat for 3 or 4 days. After that they will either puff right up, or sometimes slowly puff back up over the course of a week or so. Echinatas are usually less prone to this, but bowerbanki seem to be super finicky (at least in my tank) and will look almost dead for weeks at a time.
You would be surprised with acans reach (ESPECAILLY echinatas). There feeding tentacles aren't very long, but when they go to war their tentacles can reach VERY far and are VERY potent. Take a look at this picture one of my local forum members took of his acan kicking the crap out of a wellso: