Added a gallery and now extra "gallery" boxes are showing up!

FYI I’m a total beginner at WordPress. I have the Extensio Theme and NextGen gallery plugin, which I’ve been using for about a month – no problem. I recently added a gallery (Pasea Hotel & Spa) to a post, which also includes other galleries, but somehow I must have messed with the gallery settings, because now there are random gallery boxes showing up on the page.

https://www.dps-sc.com/sp_cpt/projects/nggallery/thumbnails/page/1

A “floating” box appears in the right sidebar area. When you hover over the box, it changes to blue, and then when you click on the box, another box appears on the left side of the screen, and then when you click on THAT second box, it disappears, but the box on the right sidebar still remains.

When the gallery is set to “thumbnail” instead of “slideshow”, the box appears. It doesn’t appear when the Slideshow feature is selected.

Right-clicking on either box gives you the option to open the same webpage in another tab, so obviously there are extra links I’ve inadvertently added somewhere. Could I have created these multiple links by deleting and then adding the same gallery to the post?

This issue also appears on our home page. I’ve looked in the css folders and can’t figure it out. The only thing I can think of is that I was playing around with the gallery settings, but why would a random box appear?

Thank you in advance for helping a beginner!