Wow.. I'm real sorry to hear this.
I've never had an issue with coloration changing or tissue tip loss after dipping with Interceptor (I've had turaki's, lokani's & enchinata's which are the more sensitive skinned acro's dipped and this hasn't happened).
* However Coral RX or Iodine will make the color's change and possibly even bleach some, if not ALOT of them out, if left for more than the required dipping time and the instructions not followed correctly. * For Informational Purpose's of this thread.
However, the only explanation I can see fit is that the infestation was already taking a toll on the untreated Acro for quite sometime. Not your fault, It's usually hard to notice if you are not certain of what it is your looking for. What you must remember they don't kill your coral right away. They slowly drain it(polyps retract.. so since the polyps retract there's no food or light absorbtion, no food or light absorbtion then the zooanthelia in side the coral does not feed and your coral stops growing, begins to loose color and slowly starves to death. So now that the red bugs have been removed, the damage is more visually apparent.
It happens, but you know what... now your more experienced and you know what to look for! The tall tale signs!
Regards,
OPG
Hope this helps buddy..