question on Observable.addAll

Hi,
I have a simple question on Observable.addAll().
I am trying to add a list to the existing one. When I run the code below, it prints out 1,2,1,2,3,4,5,2,3,4,5 instead of 1,2,1,2,3,4,5.
It seems like there is something wrong with “Each” element since the numbers variable contains the right value.

Code:

<App>
    <JavaScript>
        var Observable = require('FuseJS/Observable');
        var numbers = Observable(1,2);
        function increment(){
            numbers.addAll([1,2,3,4,5]);
        };
        module.exports = {
            numbers : numbers,
            increment : increment
        };
    </JavaScript>
    <DockPanel>
        <Button Text="increment" Clicked="{increment}" Dock="Top"/>
        <StackPanel>
            <Each Items="{numbers}">
                <Text Value="{}"/>
            </Each>
        </StackPanel>
    </DockPanel>
</App>

This definitely looks like a bug on our side. Raising a ticket for it and will get back to you when we know more!