When using the Megamenu to display categories and also using columns to display static content there is a bug that doesn't allow static content in a megamenu item with only 2 columns.

If you chose 2 columns for a menu item and put content in the field "Right Content" under the tab "Static content" the menu item is wide enought to contain it – but nothing appears.

If you choose 3 columns the content appears corectly.

The reason can be found in the code of the menu module. This file to be exact:
app/code/MGS/Mmegamenu/Block/Abstractmenu.php

In line 438 an if/else checks the number of columns but the scenatio with two columns effectively excludes it to show the right content.

A tempoary fix is to add the code that checks and displays right content along with the closing of the UL in line 458

I am not sure what consequence the change has to menu items with more columns. 

This code:

                if ($columns > 1) {
if($item->getRightContent()!='' && $item->getRightCol()!=0){
$html.='<div class="right_content static-content col-md-'.$this->getColumnByCol($item->getColumns()) * $item->getRightCol().'">';
                        $html.= $this->_filterProvider->getBlockFilter()->filter($item->getRightContent());
                        $html.='</div>';
}

                    if ($item->getBottomContent() != '') {
                        $html.='<div class="bottom_content static-content col-md-12">';
                        $html.= $this->_filterProvider->getBlockFilter()->filter($item->getBottomContent());
                        $html.='</div>';
                    }

                    $html.= '</div></div>';
                } else {
                    $html.= '</ul>';
                }

Can be replaced with this

                if ($columns > 1) {
if($item->getRightContent()!='' && $item->getRightCol()!=0){
$html.='<div class="right_content static-content col-md-'.$this->getColumnByCol($item->getColumns()) * $item->getRightCol().'">';
                        $html.= $this->_filterProvider->getBlockFilter()->filter($item->getRightContent());
                        $html.='</div>';
}

                    if ($item->getBottomContent() != '') {
                        $html.='<div class="bottom_content static-content col-md-12">';
                        $html.= $this->_filterProvider->getBlockFilter()->filter($item->getBottomContent());
                        $html.='</div>';
                    }

                    $html.= '</div></div>';
                } else {
if($item->getRightContent()!='' && $item->getRightCol()!=0){
$html.='<div class="right_content static-content col-md-'.$this->getColumnByCol($item->getColumns()) * $item->getRightCol().'">';
                        $html.= $this->_filterProvider->getBlockFilter()->filter($item->getRightContent());
                        $html.='</div>';
}
                    $html.= '</ul>';
                }

Please make an updated module available.

Thanks. I can confirm that it works in my scenario.