Comment 1 for bug 919356

Thanks for your report. This isn't the right fix, though - the intent of "Default: mirror" there was to change the default in the case where you ask to use a custom mirror. If it's being used when you didn't ask for a custom mirror, then something else is wrong and whatever that something else is needs to be tracked down instead.

The hint that this may be specific to users outside the UK may very well be instructive. I'm in the UK myself and I tend to select the UK in the installer without really thinking about it.