IMO&E, the bullet choice was the problem, not the bear's skull. A lead bullet needs to be at least "hard-cast" to be reliable. This one is quite soft. I also suspect it was a bit of a fluke hitting just the crest and likely at an angle, creating a sort of crumple zone in the skull.

I have been involved in a number of genuine bear charges and there was never anyway to consider waiting for the bear to turn away... In real charges they do not turn. I have twice had bears die while touching my boot tops. Last spring a huge wounded Kodiak bear charged repeatedly and we shot him many times...

No reasonable round coupled with a reasonable bullet is going to bounce off a bear skull.