Mega Menu headings do not line up horizontally any more

The columns in my Mega Menu don't line up horizontally across the page in Shopify any more. It seems to have happened after a Smart Menu update. The problem happens wherever I have a submenu that has no text in the Title, and "Display as Heading menu item" is selected. (See the third screenshot for what is entered in Smart Menu in this case. See the how this looks on my website in the first screen shot). The line underneath the headings that used to be unbroken across the full width of all the columns is now broken, where the submenus without text in the heading shift upwards. See the second screen shot for columns that line up, maybe because all columns have text in the Title. Maybe I could try putting text where it is blank, although I'd rather not. I tried entering spaces instead but it had no effect. 
Any idea how to fix this?