Hey there, is the artifact in the proper slot below your Ghost, or is there a swirling pattern there, which makes the artifact appear to the left of it when you put the cursor over it? If that is so, the artifact is not 'equipped', it's in an odd little selector thing a bit like an unequipped weapon. You can select mods by examining it, but they will reset. However there should be an option to Equip it instead. That will move it into its correct place and any mod unlocks will stay unlocked.