Basically, I have a model which has good topology, good UVs, has subdivision levels, and has a lot of details on the highest level.
When I export my displacement map, everything seems normal, but when looking closely, I can clearly notice that some parts don’t take displacement like they should. The thing is, the “inflated” parts are there, but the “deflated” parts are not. Every time there should be a “hole” or a scar for example, it doesn’t appear.
What I noticed when looking closely at my renders and at the .tif displacement files, is that Zbrush might have taken into account a second “Ghost” mesh, which is subdivided, but has no details, thus negating all the parts of the displacement where the polygons are supposed to be pushed inwards rather than outwards, as if there was a second mesh without details, on top of the one with details.
This is the first time I’ve ever seen something like this and I’m definitely lost, does anyone know how to fix this ?
Here is how the model looks like when rendered in another software (you can clearly see the parts where the displacement isn’t working properly) 
and here is how the model looks like in Zbrush 
Any help is appreciated !