Random extra return between lines

In one of my sections, there appeared an extra return between two lines of text, right in the middle of paragraph. I delete it and hit return–same problem. I delete it and hit shift/return–same problem. Why would this be happening and how can I fix it? Thank you!

It sounds like it might just be that the spacing is set to add extra padding between paragraphs. Try selecting the paragraphs and the space and going to Format > Text > Spacing… and adjusting the before and after paragraph spacing. You can also use Format > Options > Show Invisibles to double-check whether there actually are two carriage returns between the paragraphs that are mysteriously acting as one.