Hmmm..I thought I fixed that double entry...I remember looking at it a while back.
At any rate, you can just delete one column in the template...no harm there.
I also thought I created a bug report because I'm pretty sure extensions or plugins break a restore operation, but I just checked the tracker and couldn't find anything. Deleting any columns other than the core fields works fine.
I'll go through this app again...a lot has changed since it was converted to the 6 framework.