Layer Edge Is Appearing As Line When Stroke (Outside) Is Applied to Layer

I have masked a layer by selecting a subject and added it as a new layer. However, when I wanted to apply a stroke (outside) to the layer, the layer edge is also appearing as a thick line. I want it to apply to the subject only and not to the edges. Please guide me on how to remove or how not to apply the stroke effect to the edge of the layer?

As you can see in the image, this thick white line is appearing when I apply a stroke. Else it isn't there (I have attached both pics).