addSubview on cellForItemAtIndexPath issue in Swift - ios

Question

I have a collectionView with custom cells.
I am trying to add dynamic labels in each cell, but they are only added to the last cell shown. If i make scroll, labels disappear of that cell and appear in the new cell shown.
The number and text of labels will be achieved with a web service.
This is my cellForItemAtIndexPath function:
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! UndatedCell
cell.titleLabel.text = "Sacar al perro"
cell.locationLabel.text = "Casa"
var aux: CGFloat = 0
for label in labelsArray {
let labelWidht = calculateLabelWidht(label) + 20
cell.labelsView.addSubview(label)
label.leftAnchor.constraintEqualToAnchor(cell.labelsView.leftAnchor, constant: aux).active = true
label.centerYAnchor.constraintEqualToAnchor(cell.labelsView.centerYAnchor).active = true
label.widthAnchor.constraintEqualToConstant(labelWidht).active = true
aux = aux + labelWidht + 8
}
return cell
}
In viewDidLoad i create the demo labels:
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView!.registerClass(UndatedCell.self, forCellWithReuseIdentifier: reuseIdentifier)
self.collectionView?.alwaysBounceVertical = true
let label1 = LabelLabel()
label1.text = "Zara"
labelsArray.append(label1)
let label2 = LabelLabel()
label2.text = "Perro"
labelsArray.append(label2)
let label3 = LabelLabel()
label3.text = "Amigo"
labelsArray.append(label3)
}
Finally, this is a pic of the result:
collectionViewPhoto
Thank you very much for your time!