You do not need to change the shortcode since this is a page layout issue. Looks like the markup is missing a closure tag. The heading styling has entered into the portfolio area (due to some missing closing shortcode “[/heading2]” markup or div element not being closed) making it have a large margin on right and left and squeezing the portfolio items.
If you have trouble, I can rectify it for you if you post a private message here with the URL and temporary wordpress login.