Unwanted photo gallery in middle of post text

I’m currently trying to post a standard text post, and an unwanted and inexplicable blank photo gallery keeps appearing in the middle of my text.

The post was created in the standard format; the gallery format was never applied. I copied and pasted the text from an original Word document. I tried starting over with a fresh post, and the same inexplicable blank gallery appears in the post.

The gallery appears in both the preview and when I try to post it. I don’t currently have the post public because I have a client waiting to view it, and I don’t want them to see the messed up post.

How do I get rid of the blank gallery in the middle of my text?

Thank you.