Hello,
On the build mal called "The Wildlands" there are several zones, including the one called "Curgens Tomb" : I haven't tried the other zones, but this one is not buildable. Even after you've killed all the monsters inside and collected all the treasures, it's still not possible to build outposts inside (well, I haven't tried real outposts with a pioner, I'm talking of outposts build with the spell "Arcane Monolith").
I guess it's not normal... but may be it is.