Pressure-treated wood inherently is not good at accepting epoxies, paints, or other film-forming coatings due to the high moisture content that it retains. The moisture can either prevent a proper cure of the coating, or delaminate the coating as moisture is emitted over time. Oil-based paints in general are not a good option for coating pressure treated wood. Pressure-treated lumber that has had time to dry out may have a better chance for adhesion. There are specific hardware store primers that claim to adhere to pressure treated wood. If one of these products is used, only apply topcoats that are compatible with those primers.
Regardless of the application, be sure to perform a small test for good adhesion before attempting a full project.