Not certain if this is by design or not!

I'm getting an error "Illegal Characters in Path" when attempting to duplicate an Animation.

Repro:
1. Download project
2. Expand 'Wolf' model in project view
3. Ctrl+D / Duplicate one of its animations
4. Observe error in console

Well aware this may be an invalid action (i.e. you shouldn't be allowed to dupe those animations)- in this case should the error be more specific?