Dexp Masonry Grid - Uncaught TypeError: Cannot read property '1' of null

Hello - I'm getting a JavaScript error after configuring a view display with the format Dexp Masonry Grid.  I've followed the tutorial here with the only difference being that I want to use this format for Article not Porfolio.

The error only happens after I try to resize one of the items in the masonry grid.  Initially after configuring the view for the first time and without resizing anything, the page loads.  However after resizing a single item in the grid the JavaScript error is thrown on page load and it prevents my entire page from loading. 

Here is a screenshot of the error in my Chrome console:

Here is the screenshot of the code in the dexp masonry module's JS where the error is thrown:

(I added some console.log statements while I was trying to debug.

Here is my view format settings:

Any help would be greatly appreciated.  

Thank you!

Some additional information...

When I use the admin UI to resize items in the grid, it is not snapping to columns and rows as depicte in the YT video.  Instead it allows me to resize to any width and height that I want.  Then the data thats saved in the DB for the item consists of large negative numbers like -41 for height and -85 for width.

This is what the HTML looks like when I reload after resizing:

The class="dexp-masonry-item item-w-85 item-h-41" looks odd compared to the Jollyness demo where in that case the classes are like item-w2 item-h1