From time to time you will encounter this type of issue, a target that is reported in game as not being in a place where they can be attacked, but appear right next to you.
There are a multitude of reasons that you might see this, this can include internet speed issues and server lag is just one of many.
Often times simply running a cleaner such as CC cleaner or DiskMax can clear this issue up for a time.
If you continue to see this problem, please feel free to send in a support ticket with a screen shot, or submit another inquiry through the forum and we'll forward that on to the people in the know.
We all appreciate your time and efforts with the game, and the time spent to bring these issues to our attention.
I'm going to close this thread due to the amount of time since the last post.