I doubt it. Those get mixed up with zoanthid colonies all the time, in perfect harmony.
Some pests, fungus won't mess with paly's because their toxins are extremely high. So your zoas could have a fungus, pox, pest messing with them but won't touch the paly. This makes it seem as-if the paly is the culprit when it really isn't. Give that rock a dip. That should help you. I dip mine if they start looking upset, way b4 any ill effects are even seen. Even a simple freshwater dip will do wonders, just do your research on how to properly do a fw dip.