We have an Excel file on OneDrive for Business, and we have it shared with some users in our domain. If they open the file with Excel Online and switch to "Viewing" - changes others make to the document are never reflected, even when clicking the Catch Up button. If they switch to Editing - changes made are reflected immediately (or, for those that edit with the desktop app, reflected within a minute of being saved) without even needing to click the 'Catch Up' button. If the browser window is refreshed, the file is up to date. If the user switches to Edit from View - the changes that were made are immediately reflected. If they switch back to "Viewing" - the file reverts back to what they first displayed. Seems like something is a little off. We have tried various browsers (IE11, Chrome - latest release, Edge Chromium). We have also used the link with members outside our organization and experienced the same issue.