It might have something to do with the save-game that failed to load, if the save-game doesn’t load correctly does your code still take that into account? Because you might be trying to load from an empty string.
Warning: Failed to read file '[..]/Documents/Unreal Projects/Game/Saved/SaveGames/EasyQuestsSave.sav' error.
[..]
Attempted to create a package named 'None'