By default, modals that are added to pages are hidden when the page is 'made editable in Gutenberg'. This is wise as it can mess up the page layout quite a bit and be confusing to content editors. However, if we do want to make them visible, so they can be editable directly from the page editor, we can.
Inline modal inside Gutenberg
Note - If we have lots of modals on the page, this may not be the best way to go about allowing content editors to edit them. Creating custom fields could be a better method. Also, this method will only apply to modals that exist inside pages, not modals that are setup globally.