Chop jock,
We'll leave the angle of attack discussion, it's clearly pitched too high for you.
(See what I did there!)
The photograph posted on this thread, which shows that trailing edge damage, more than probably has nothing whatsoever to do with this thread. Looking at the picture, the yellow colouring is very dull/matt, (could be dirty I suppose), it covers a larger area than the traditional 135 blade colour scheme and the curvature at the leading edge tip is a lot longer and not so curved as a traditional 135 blade;
Despite the leading edge damage being a red herring here, in answer to your question; "how would you account for getting a dent in the trailing edge of a blade then?;
May I suggest that the blade may be moving backwards before hitting something or maybe the stationary blade is hit by something else. Damage to blades doesn't have to occur when they are under power or even when they are rotating.
So, if we can stick to the facts of the matter;
"I had a minor blade strike on a tree branch in a wilderness area in Cape York. In order to get the helicopter out of that location, I made a repair to the rotor blades," he (Mr Green) wrote in the submission to the federal government's Aviation Safety Regulation Review.
Now, doesn't that sound as though the more 'traditional blade strike' type (minor) damage had occurred?