The visibility of  Aim Assist is global, and is stored in the registry.  In other words it's not tied to any project or workspace - it remembers the last "state" it was in from the last time you used it. The show Aim Assist Time however, doesn't seem to be being stored anywhere, which is why it's behaving randomly. This will be fixed for the next release so it behaves like the Aim Assist on/off - so it will be global and remember its state from the last time you used it.