I have some strange issue with UITableView only in iOS 7.
UITableViewCellSeparator disappears above the first row and below the last row. S
I also had the problem with missing separator and I found out that the problem only occured when heightForRowAtIndexPath was returning a decimal number. Solution:
override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
return ceil(yourHeight) // Ceiling this value fixes disappearing separators
}