Python packages in the virtualenv ('build-cmake/dune-env') don't get updated

I use the dune_python_install_package function together with the necessary CMake flags to install the Python modules of my projects into the virtualenv at configure time. However, re-configuring does not update the packages in the virtualenv. After making changes to files within a package that has already been installed into the virtualenv, I have to remove the dune-common build directory completely and re-configure all projects with Python packages to incorporate said changes. Is there a way to circumvent that? As far as I'm aware, dune-python used to overwrite packages in the virtualenv every time CMake was run.