It was a bad paint sealer by Sherwin Williams and one more company I believe.
Either strip it to the bare metal, epoxy then base/clear or get some cans of Peeler, DA sand what it didn't remove with 180 on a DA, epoxy it then base/clear it is what many do.
GM and Chrysler warranted countless paint jobs in the 90's because of this problem and you usually see it on top/flat surfaces. I doubt it has any warranty value now.
Many body shops in business today got started during the 'peeler' era.