Did a shake -j8 --profile on your PR (top part of image below) vs dev (bottom part).
Not a drastic change but an (unparalleled) gain of 3 minutes still.
I’ve posted the two complete reports at : https://cernbox.cern.ch/index.php/s/unP84Q06pY7uVmA (build of PR#1092) and https://cernbox.cern.ch/index.php/s/jQRqRSAa4AD8q3B (ref build)