e2studio keeps building unchanged files on each build


I have a project with multiple build configurations. The differences between them are small, I use this for instance to build for several languages.

The problem I'm getting is that on every build on say FoobarUK it not only builds the objects that are out of date for FoobarUK, but also the ones that are out of date for FoobarDE. 

This is getting pretty annoying, because even if FoobarUK is fully up to date, if I build it many objects are compiled anyway on each build, only because FoobarDE is not up to date, and thus eats time.

I don't see any differences between the projects, except for the defines that determine the language. But I also have no clue where to look, so any help would be appreciated.

I'm using GCC for Renesas RX version, on e2studio 7.1.0, but I saw this behavior on older versions as well.