In the Loop page builder I cannot change the positioning of the sidebars (the layout).
You can fix by editing functions/theme.php and locating line 2618 which should look like this:
$shortcode .= ']';
Add the following line of code right above it so it looks like so:
$shortcode .= !empty($layout) ? ' layout="' . $layout . '"' : '';<br>$shortcode .= ']'; <br>