Why is an IBOutletCollection pointing to static cells from storyboard returning null?

I have defined this in code:

@property (nonatomic, weak) IBOutletCollection(UITableViewCell) NSSet * certaintyCells;

and synthesized. I made absolutely sure that this controller is used in story board, and connected three cells to this collection.

Next, in the didSelectRowAtIndexPath: method call, I added this code, with NSLog added for debugging:

NSLog(@"Certainty Cells: %@",certaintyCells);

        for (UITableViewCell * cell in certaintyCells) {

            [cell.textLabel setTextColor:[UIColor colorWithRed:0 green:0 blue:0 alpha:1]];

            [cell setSelectionStyle:UITableViewCellSelectionStyleBlue];

        }

The output is this:

Certainty Cells: (null)

And of course, behaviour expected does not happen.

Any ideas as to why this is happening? I did make sure that I am using static cells, and not dynamic prototypes. As a side note, these three cells are also connected to (working) IBOutlets of their own.

Thanks,