Blame ignores top line if it contains no text (BB-6595)

Blame is reporting wrong lines for many lines in Git. I'm not sure how to best report it, as it's happening in one of my private repositories

https://bitbucket.org/sliceone/src/annotate/2b7b056c862deb0ab83e7d4de1ce583d272f36b9/httpserver/controllers/index.go?at=master

(blame for line 14 is wrong; there are probably others)

As you can see in screenshots, the commit blame is linking line 14 to doesn't even contain the file I'm using blame on.