"Is this a problem" -- YES!!!
You really need to get in touch with a trainer who works with aggression issues - it isn't something to allow to go on, it'll just be harder to correct. Ask around & call someone in your area. Your vet or the humane society should be able to refer you to someone who can help assess the behavior and teach you what you need to do to correct it. I've done rounds of obedience classes with a three different trainers, two of them had situations where dogs came to obedience classes that were too aggressive to be in a class with other dogs, but were really helped by one on one sessions. Especially with a very strong dog like an Akita, you're taking an awfully big risk every time you step into a situation he gets aggressive in. I really encourage you to get an expert's help.