QGIS layer blending: keep polygon outline un-blended?

One possibility is the need to change the line in the config file /etc/abrt/abrt-action-save-package-data.conf

ProcessUnpackaged = no

to yes, otherwise abrtd will only capture corefiles from programs installed by the package manager (dnf, apt, or whatever). Use abrt-gui or abrt-cli to look for core dumps.