My account at work (rtonneyck), is a Windows domain account. That's what I use to login too. I noticed the permissions for my Shared windows drive has my user name listed multiple times. Why is this?? Is this a bug with Mavericks?
Screenshot: 
MacBook Pro with Retina display, OS X Mavericks (10.9.4), Using Windows domain
Best Answer
Sounds like there are multiple entries with your user account in the access control list of the share.
Unless you're experiencing performance/functionality issues, I recommend contacting the person who administers that share, letting them know about what you found, then ignore it. :)
If you're experiencing performance/functionality issues, find out if anyone else who uses the share experiences the same symptoms, compile your findings, then submit them to the share administrator.