After quite a lot searching around Google, Stackoverflow and apples documentation, I have almost given up.
I am making an app to index costumers and because of a pot
As a simple work-around we resolved the visual overlap of the index by setting the background color of the index to clearColor.
self.tableView.sectionIndexBackgroundColor = [UIColor clearColor];
* This looks visually better, but the index will still overlap your tableViewCell.
Another possible work-around would be to hide the index bar when entering edit mode:
// allow editing
[self.tableView setEditing:YES animated:YES];
// hides the index
self.tableView.sectionIndexMinimumDisplayRowCount = NSIntegerMax;