Open mesh on UV seams

Hi everyone,

i'm encountering an hateful weird issues with HEIGHT MAP in Substance Painter.

As you can see from the image the mesh in some spots it opens and in some other areas it creates cracks.  This happen in conjunction with the UV seams:

Inspecting the Height map i noticed that this could happen because where the uv islands comes togheter the paint across became unmanageable and is impossible to fade the transition: 

Someone know why this happen? There are ways to solve it ?

Thanks in advance to everyone.