not sure if relevant, but this initially happened during an upgrade from jessie to stretch.
i figured the line "PrivateDevices=\n" maybe cleared whatever value the variable held before. maybe that used to be the case? you're welcome for the bugreport! i hope it's an actual bug and therefore useful to have this here, and not just something specific to my system, turning this into personal tech support and wasting other people's space and time. (free tech support, woo!) thanks!
