At 8 months, he very well should.
EXACTLY! But if he doesn't then it's our fault not the dogs....
And, truthfully, the example listed of his 'misbehaving' was play mouthing LIKE ALL OUR DOGS DO when they want to play until we teach them better.
Sounds like a friendly happy dog that just doesn't understand. Once again, when I am having issues communicating with my dogs I go and get help. Though, frankly, I know this WILL happen so tend to start up puppy classes to prevent this from cropping up at all. Proactive and all
Exercise, teaching appropriate play, spending those hours a week TEACHING what I do want/expect rather then correcting and punishing AFTER they misbehave
I may have mis-read but when I saw 'recent new GSD owner' I figured they just got the dog so that's a bit different circumstance then if they've had it since pup was 8 weeks old. Though not sure I'd train too much differently for such a young dog.
If training was so easy then all our dogs would be perfect. It is NOT. So I go to dog classes and have professionals help me quickly and easily prevented the frustration that otherwise crops up for both my dog(s) and myself.