Grid system broken with flex and IE10-11

Created by: ezramorse

The following code block renders on two lines when compiling the SASS stylesheet with option: $enable-flex: true !default;

        <div class="row">
                <div class="col-sm-6">
One of Two Columns
                </div>
                <div class="col-sm-6">
Two of Two Columns
                </div>
        </div>
</div>```