I generally run Query Monitor on my sites to identify potential issues with other plugins on my site. Unfortunately, it is identifying PHP errors in the GP Premium plugin when I attempt to create or modify elements in the Elements module. Unfortunately, it appears that I cannot upload a screen image, so…
To replicate the problem, please install and activate Query Monitor, install and activate GP Premium, navigate to Appearance > Elements and click on Add New. Drill down on the Brown-highlighted Query Monitor status area of the Admin Bar to display the PHP errors.