binding: .keys() function is not defined

I’m submitting a bug report

• Library Version: aurelia-binding 1.0.9 aurelia-polyfills 1.1.1

Please tell us about your environment:

• Operating System: Windows 10

• Node Version: 7.0.0

• NPM Version: 3.10.8

• JSPM OR Webpack AND Version webpack 1.13.3

• Browser: IE 11

• Language: TypeScript 2.0

Current behavior: On app startup I always get this error in Internet Explorer: Das Objekt unterstützt die Eigenschaft oder Methode "keys" nicht. This points to the following line in aurelia-binding: var keys = bindings.keys() inside the flush function. I tested the following to isolate the issue:

• The codeblock in aurelia-polyfills where the Map Polyfill is applied, is executed correct (before this error happens)
• If I execute bindings.keys during debugging I received undefined.
• If I execute new Map().keys during debugging I received the sharedKeys function from the polyfill.
• If I execute bindings.constructor.name during debugging I received Map.

It seems, that some bindings are not correct handled after this issue appears.