KO 3.0.0 bug in IE8 - options/optionsCaption

Looking at upgrading our app to 3.0.0 but it is breaking IE8 for us.
I have a reproduction here http://jsbin.com/orEwOLAW/3/edit

What happens is that when I have a `select` element with both `options` and `optionsCaption` then I push more than one item in to the array, instead of the caption being chosen the first option is.

In my jsbin, if you change the KO version to 2.3.0, then the bug doesn't appear. Or if you comment out the second filterValues.push() the bug doesn't appear.