I have some strange issue with UITableView only in iOS 7.
UITableViewCellSeparator disappears above the first row and below the last row. S
You need to remove a cell selection before you doing cell's update. Then you could restore selection.
NSIndexPath *selectedPath = [self.tableview indexPathForSelectedRow];
[self.tableview deselectRowAtIndexPath:selectedPath animated:NO];
[self.tableview reloadRowsAtIndexPaths:@[ path ] withRowAnimation:UITableViewRowAnimationNone];
[self.tableview selectRowAtIndexPath:selectedPath animated:NO scrollPosition:UITableViewScrollPositionNone];