Editable installs and optional deps

Did something change here? I swear I had optional deps working both ways - from pypi (pip install scons[dev]) and as an editable install (pip install -e .[dev] - which I do frequently to do quick local tests of unreleased stuff), but now only the former works, the latter fails with WARNING: scons 4.10.2 does not provide the extra 'dev'). Do I have something set up wrong?