The epoxy hasn't fully cured. Allow the final epoxy coat to cure thoroughly. Allow several days if necessary for slow hardeners at cooler temperatures. Apply moderate heat to complete the cure if necessary. See Controlling Cure Time under Epoxy Chemistry. 2. The paint or varnish is incompatible with epoxy. A. Use a different type of paint or varnish. Some paints and varnishes may be incompatible with some hardeners. If unsure, test for compatibility on a coated piece of scrap material. B. Use 207 Hardener. It is compatible with most paints and varnishes. 3. The cured epoxy surface wasn't thoroughly prepared. Remove any amine blush and sand the epoxy surface thoroughly before applying paints or varnishes. See Final Surface Prep.