Having installe literally MILLIONS of square feet of Hardi-Plank siding, I have never encountered this. Hardi itself really does not even require paint but for aesthetic reasons. If installed properly, joints should not require much caulk. Improper installation and bad cuts require much more caulk, and caulk when overapplied will detach from the surface. Proper installation and caulking should last (aesthetically) for 5 to 7 years.