I have an employee that's trying to add a shortcut to her shortcut menu... but whenever she tries to add a 4th shortcut, it erases one and keeps only 3. Is there somewhere that limits how many shortcuts a user can have? (Have tried logging out and back in also)

Sometimes NS does that wierd stuff - if she doesn't have a lot of stuff bookmarked yet - you might remove her access and then grant it back

try clearing the browser's cache - it might help