The grp target is missing the portage_overlay action. This means portage_overlay is never copied to /usr/local/portage an therefore never used. Reproducible: Always
Created attachment 113472 [details, diff] Add portage_overlay support to grp actions
This is in SVN now and will be in 2.0.3
This is fixed in 2.0.3 which should be hitting the tree shortly.