Level not Saving, Edits disappear

YouTube Link

You cant really see it in the video because Shadowplay is spazzing out a bit but basically I edit something then save it (I try Control + S, Control + Shift + S, Saving as new Level) but as soon as I for example close Unreal Engine and reopen the level or switch between two levels the Edits are gone.

Im unsure what is causing this and I cant finish my Project because I can never save it.