On Confluence Cloud pages, there is a div with the ID comment-container that is covering a small section of the page. I don’t know what it is used for, but it is always there. It is absolutely positioned, its exact position depends on the dimensions of the viewport. The problem is that it even though it is invisible, it is preventing user interaction with that section of the page. Our app provides a macro that happens to have a save button in the region where the comment-container frequently appears, and it is preventing our users from clicking the button.
Here is a screenshot of a position where the container often ends up: