Just to be clear: I don't use Construct.
That said, I am facing another issue with HTML5 Audio... if too many sound effects are loaded (14 to be exact in my case), pressing the home key to go to start menu and then back key to resume the app, repeating this action twice causes app crash. If I remove the sound effects completely, no such issue; or if i remove them on home key press and then reload them again on resume, no crash also, but that means have to wait for them to reload again....
Stupid Microsoft... gave us false hope, wasted time for nothing! WinJS is useless because of these crippling HTML5 Audio bugs. I am going back to c++.
I am working with few MS guys at my city. I have sent them few test samples. Hopefully they will find a fix. If possible please, upload your project on the ConnectIE link that Ashley shared in the above comments.
But meanwhile I think SPARTAN Browser is the future for all WinJS Apps. It will be equivalent to Chrome in terms of features & HTML5 compatibility and also light weighted. Lets hope for the best!