scons LIBPATH generates additional library paths

Question

I'm building a C project using scons, some internal static libraries are build and the exe files are linked to it. However, setting:

env['LIBPATH'] = ['#build/libs']

generates a -Llibs and a -Lbuild/libs argument to gcc:

gcc -o edecode main.o pack16.o pack16le.o pack32.o pack32le.o pack64.o -Lbuild/libs -Llibs -lutillib

Why's that ? I only told it to look in build/libs

Edit: Note, this happens only when the SConstruct calls a SConscript file that builds this library in a variant dir, i.e. I have a call like this:

SConscript('libs/SConscript',src_dir='#libs',build_dir='#build/libs',duplicate=0)