I've just had to re-download Lightroom back onto my work computer and I think it's either lost a preset or this is a new update?
I do a lot of studio editing and the brush isn't editing the products smoothly. I've taken a screenshot of the image and you can see from the histogram it's pixelated along the edge of the product.
Can someone please advise?
Have you tried using a small amount of feather? That may enable you to get closer into the garment without contamination. Otherwise take the photo into Photoshop CC where you can more easily make selections and use the refine edge feature.
In the screen shot, your brush size is set to "1." Even with 100% feather, there is not really any feature of the brush is only 1 pixel.
Change your brush to a larger size and then notice the difference in the feather softness.