I'm still having this problem but I have now noticed that it only occurs when using the Microsoft Edge browser. BUT the problem still remains when testing on Windows Phone, maybe it uses Edge in the background or something to run the game?
I did some web searching and found a thread on fusions forum from someone having the exact same issue, obviously with different game dev software but same problem. He described it as keys not releasing when let go of them.
Here's another thread on html5gamedevs: goo.gl/jUolmz
I don't know what to do. I want to develop my games for Windows Phone but if it is having this issue of keyboard/touch controls having a mind of their own then no one will play my games because they're too glitchy.
Any thoughts on what may be causing this and possibly how to get around it?