RH beat me to it...It looks like a crack to me...He also gave you some dang good instructions for a fix though. I'm gonna hafta remember that fix too! grin
Yea, like you need any help.Thanks though,

Bedding the lug is a great suggestion too. Might as well do it since you will have epoxy left over. Just use plenty of release agent on the metal and don't use so much epoxy that it overuns and creates a mechanical bind-lock elsewhere.

I might fix the crack first though and then get everything cleaned up before doing the lug. You wouldn't want tape or anything holding you off when you bed the lug.