Apologies, this seems to be the issue with universal apps (specifically edge).
What's strange is that my previous windows 10 build didn't have that issue (I guess I had been using a pre uwp version of edge)
We are aware of this bug with UWP apps, and we have it on our list to fix up. I've added both of your votes to it, so we'll be sure to let you know if we have any news on it in the future.