Yes, this problem is related to the core Media Manager functionality drag and drop problem which was detected by numerous users of WordPress.
This bug is already detected:
We’re working on a solution for our gallery and core WordPress team also looking for a solution. https://core.trac.www.ads-software.com/ticket/54902
Also, we’re working on a few alternative solutions for gallery images management.
The first option it’s a drag and drop image sorting for a media manager widget in gallery settings. Where right now you can see a preview of the uploaded, gallery images.
In this case, if we’ll not be able to fix the core media manager we’ll release such functionality for the images widget next week.
Also, we’re working on an absolutely new media management solution for Robo gallery with multi-line edit, and lots of different additional options.
We’re really sorry for the inconvenience. We’re working hard on a solution for our gallery.