Picked up elsewhere there's a suggestion that this type of damage is sunscald.
It is the sunny side and top of branch.
I have seen this here generally only when a large portion of tree gets opened up to full summer sun it hasn't seen before. I have seen for example large mature mango trees get topped or side lopped and then it happens.
In fact it happen to the ficus at Cathedral Square in Brisbane when the council hacked that.
However, I have seen the same on all the tops of all southern branches on a euc grandis which doesn't make sense ... must have been something else other than sunscald.
How long has the tops of those branches been like that?