Double Bass Plywood delam on upper bout

... how/why is it happening ...

I'm with the majority: I see aligned divots from an impact. The wood looks to be pressed in from a hit, not sticking out due to delamination.

How to prevent it in the future? Don't bang your bass into anything (and good luck with that, btw).
 
Not sure why you felt the need to post such a terribly helpful post. In your brilliance, please explain why these 3 aligned "divots" did not appear at the same time? The magical impact (that I can't recall - or even figure out how it happened), had both immediate and delayed impact?

And, I guess I'll accept your unimpeachable impression that they appear pressed in, as opposed to what in reality are clearly chips peeling away.

Jst a very useful post. :rolleyes: