There is a weird dashed line that appears above the player's arm model. Most likely an issue with texture stitching. The line is very thin and can be hard to notice.

The issue occurs at the top right position above my right arm. The dashed line has the same colour as my custom skin's arm colour.

To reproduce:

For players with light hand textures, go up to blocks with dark textures. Likewise, for players with dark hand textures, go up to blocks with light textures. It is very easy to notice if you move your hand around.