Wondering the same thing.Any word on whether this issue has been fixed in 8.1.1?
I believe that this is finally actually really fixed in iOS 8.2 beta 1. I thought it was fixed before and discovered it wasn't, but this time it's been more than 20 hours since I installed 8.2 and I haven't had a single double notification. I think Apple may have finally taken care of it.
God I hope this is true. I wonder when 8.2 will come out. Do you think they are going to wait all the way until 2015 to launch 8.2 to coincide with with Apple Watch launch?