Seem to me it is the left overs of tip damage from coming out of hibernation as its right at the grey to green transition. The plant has just pushed through it. I wouldn't worry to much about it but you can keep an eye on it to ensure it doesn't spread.

Thanks Kms.

but it was not there a month ago.

the tree lools healthy but this is my baby... Probably just over thinking it.

I can understand that and completely agree that the plant looks very healthy. If you have to do something about it just keep a close watch on the area. I think the dark area will naturally flake off as the branch expands against it.

Thanks for your input.