I'm wondering if there's anything different about Amsterdam during the Oktoberfest in Germany? We are planning on going to both places. We expect Germany isn't going to be it's usual self with 6 million visitors but are hoping for Amsterdam as usual
Amsterdam in not Germany. Neither is Munich.
You will never notice that the Oktoberfest is happening anywhere but in Munich. The rest of Germany doesn't partake in this fest, and it doesn't affect tourist numbers anywhere else either. It is strictly Munich.
Maybe fewer German tourists in Amsterdam then since they're all drinking back home.
Even in Munich, unless you are at the fairgrounds or at the train station it's not really more crowded than if you were there in the summer. At least that was my experience a few years ago.