Why has my Qt widget focus changed?

I basically have a function that checks focus to / from the edit line. From here, it makes a text animation to do the google-style input. Here's the function:

QParallelAnimationGroup *group = new QParallelAnimationGroup;

QPropertyAnimation *posAnimation = new QPropertyAnimation(label, "pos");
posAnimation->setStartValue(QPoint(0, 0));
posAnimation->setEndValue(QPoint(5, 5));
group->addAnimation(posAnimation);

QPropertyAnimation *sizeAnimation = new QPropertyAnimation(label, "size");
sizeAnimation->setStartValue(label->size());
sizeAnimation->setEndValue(QSize(QFontMetrics(pix16).width(label->text()), QFontMetrics(pix16).height()));
group->addAnimation(sizeAnimation);

QPropertyAnimation *fontAnimation = new QPropertyAnimation(label, "fontPixelSize");
fontAnimation->setStartValue(12);
fontAnimation->setEndValue(16);
group->addAnimation(fontAnimation);

group->start(QAbstractAnimation::DeleteWhenStopped);

label->setAttribute(Qt::WA_TransparentForMouseEvents);

updateRect();
return lineEdit->eventFilter(watched, event);

      

        
        
        
      

    

The only problem is that when you push one line to another edit, focus goes away from the first (which is good), then it goes to the second, but quickly goes away from the second.

Not sure why this is happening, but it renders my animation useless.

I am using Qt 5.9 IDE with C ++

EDIT: I subclassed the QLabel to get a custom property:

class Label: public QLabel {
    Q_OBJECT
    Q_PROPERTY (double fontPixelSize READ fontPixelSize WRITE setFontPixelSize)

public:
    Label(QWidget* parent = 0): QLabel(parent)
    {

    }
    double fontPixelSize() const
    {
        return font().pixelSize();
    }
    Q_SLOT void setFontPixelSize(int size)
    {
        QFont f = font();
        f.setPixelSize(size);
        setFont(f);
    }
};

      

        
        
        
      

    

EDIT: Added GitHub link: HERE