New to WordPress: When I save changes to draft pages or update pages that are published, it removes content that I’ve added

Hi there

I was recently asked to finish building a website, and I wanted to I've been trying to save changes, but every time I do, it deletes either part or all of what I've added. Whether it is a simple formatting change or moving a color section elsewhere, it will delete all or part of the page. I've cleared my cache and disabled plugins like most help sites have recommended, but it doesn't seem to help the issue. I also want to add that it's not an issue on 5 other pages, just the last two pages that need editing. Sometimes I can pull up a revision of what I have added, but then it's the same issue when I update/save changes.