Applying shimmer to text in UIButton

[Advozium]

I have a question about the use case where I'd like to add a shimmer to the label of a UIButton. The problem is that when I add the Shimmer as a subview to the button, and then apply the shimmer to the UILabel in the button, the text shrinks. I'm doing the following in my function to initialise the shimmering view:

let shimmerView = ShimmeringView(frame: self.Button.titleLabel!.frame)
Button.addSubview(shimmerView)
shimmerView.contentView = self.Button.titleLabel!
shimmerView.isShimmering = true
shimmerView.shimmerSpeed = 50

The end result is shown below:

Having taken a look, I noticed that the text label inside the button is shrinking. Is this the intended behaviour for the Shimmer view, or is there another way of setting it up so that I can have the text label shimmer and sized properly inside a button?