paint coming off Hardie siding

Some hardie siding has a primer on it from the factory. Most manufacturers will require a primer over this factory primer to ensure proper adhesion. hadry siding is cementuous. The ph level is often what causes premature paint failure. A PQR could be performed by the servicing store to further research the specific issue. I would spot primer the peeling spots with a 100% acrylic primer then try to touch up the area with the original paint if any is left over. After 2 years it will be difficult to make the color blend perfectly so your contractor may have to paint up to the end of a wall or a joint in the siding. I would take a piece of the peeling paint to the store and have a PQR done. That's a good starting point.