I had same problem and was scratching my head for days even after getting this message system was stable but wanted to resolve the issue anyhow. It has nothing to do with your osx or boot flags. I did figure this out by doing couple of revision and installation with clover bootloader. If you install clover as UEFI and your bios support uefi then simply disable csm (compability support module) otherwise install clover as efi partition. And Magic!!! message will disappear.