Duplicate Items in library when sharing between FLAs

Hey,

I've been having this frustrating problem for a while. 

I am using one FLA called "shared_components.fla" where I have defined all of my shared components for easy sharing and 
styling in one place. 
Now in my other workfile, "menu.xfl" I am pulling in a few of these Library symbols. Mostly this works fine, but when two Symbols (A and B) have an instance of a Third symbol (X) inside of them, this creates a "Duplicate Items Folder" with a duplicate of X in it, with B now referencing the duplicate of X. Now if I pull in or update Symbol C that also references X, this creates "X copy" in "Duplicate Items Folder", with symbol C now referencing that one. 

I clearly do not want my Library to keep growing like this as it becomes messy to keep track of, and I am afraid that it will have an impact on runtime performance or memory footprint. 

Since I am doing a lot of updates I can not keep having to go back and Swap what instance of X A, B and C are pointing to. 

All of the symbols mentioned are set up for Authortime Sharing. 

The Symbols are arranged differently in the two libraries, in menu.xfl I have put all of my shared Symbols under a "_imported" folder so that I can easily keep track of which ones I need to update.

Is there some other key function I have missed, or is Animate bugged?