Minecraft player skin arm orientation incorrect

While experimenting with skin designs for my Minecraft character I discovered that the arm orientation tilted to the left in First person, this bug does't affect the character model which you see in 3rd person just the first person players perspective. This means that the top of the arm appears as the inside, and the bottom appears as the outside.
In the 3 attachments we can see that I have altered the original Steve skin by colour coding the sides of the arm, to make it easier to interpret. In my adjusted skin we would expect to see the the green appear where the blue does and the blue to appear where the red is.
Thank you for your time.