Online Word Doc Problem

I take your word for it that you've combed through the language settings and all looks good.  I think you need to determine if Edge is at fault.  There's a few ways to test this: 1) Access the document using an in-private windows (if your organization allows it), 2) Try another browser, 3) Try a guest profile in Edge (If your org permits it).

If Edge is at fault, we start simple and clear the entire cache. If the issue persists, defaulting the default profile that's stored on your computer is the next move.