Weird extra square border (possibly an extra UITextViewCell?) in grouped UITextView

Question

Here's a grouped UITableView which has the sectionHeaderHeight set to 0, and it's background is completely transparent.

I don't understand what's going on with the square "background" behind the first text label:

http://screencast.com/t/mfK6Khfgs1

Here's the code I'm working with, for reference:

https://gist.github.com/08c1ca8cd60d6382d92f

Any ideas?