yasnippets doubling value (possible bug?)

[Subhan Michael Tindall]

I'm fairly new to yas, mostly likeing it so far.
Here's my trouble

When I expand this:
#+AUTHOR: Subhan Michael Tindall
#+EMAIL: subhant@familycareinc.org
#+STARTUP: content hideblocks
#+CATEGORY: ${1:category}
#+FILETAGS: :$1:${2:additional tags}
#+COMMENTS ${3:comments}
* project
  :PROPERTIES:
  :project_name: ${4:project name}
  :files: "${5:`(buffer-file-name)`}"
  :agenda_files: "$5" "work-log.org"
  :LastWorked: ${6:`(org-time-stamp-inactive 2)`}
  :END:
$0

What I get is this:
#+AUTHOR: Subhan Michael Tindall
#+EMAIL: subhant@familycareinc.org
#+STARTUP: content hideblocks
#+CATEGORY: MISC
#+FILETAGS: :category:
#+COMMENTS
* project
  :PROPERTIES:
  :project_name: domain_names
  :files:    
"//fcfpsvr2/redir/Desktop/subhant/Desktop/home/org-docs/projects/projects.org"
  :agenda_files: 
"//fcfpsvr2/redir/Desktop/subhant/Desktop/home/org-docs/projects/projects.org" 
"work-log.org"
  :LastWorked: [2014-11-25 Tue 10:42][2014-11-25 Tue 10:42]
  :END:

Which is fine, except for the :LastWorked: line with the double time stamp.
Note that the same syntax is working properly for the buffer-file-name-call, 
although a little oddly - it works as a tab stop with no prompt, but if I tab 
on by it inserts the filename.


Any ideas why this might be?
And, is it possible to make the call on $5 auto-insert the buffer file name 
without acting as a tab stop?

Thanks!



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