Where is the story of the investigation into the chain of command problems Bergdahl was trying to report?

It's far from unbelievable that there may have been serious problems in Bergdahl's unit.

 Bergdahl believed those problems necessitated his attempt to report it outside of his unit so it could be addressed and remedied.

When that investigation is complete, then that information should be considered before sentencing.

Without that investigation, we don't know if Bergdahl's actions might not have been entirely valid.

Chain of command issues could lead to far greater risk to our forces than Bergdahl's actions.

Let's see the Army investigation into Berdahl's concerns.  

Where is that report?

I can guess why that's not part of the public discussion, ...it's far easier to be a demagogue if you leave out or omit all or key factors of any particular issue.