Why would there be pink insulation coming out the air conditioner vent?

It sounds like a piece of house insulation got sucked into your return air duct somewhere along the line. If there is evidence of it at your supply air vents that indicates it has passed completely throughout your system. Including the fan wheel, electric heating coils or furnace heat exchanger ( whichever you have) cooling coils etc. This can cause equipment problems if left uncorrected. It would be wise to call someone & have the entire system looked at & cleaned out if needed. Plus find & correct the source of the problem.