We had this issue a few times with new pages we're trying to create: the UID was previously saved as something, never published, and then changed to something else, but the preview on our staging environment is not showing this change, and we get a 404. Please see the screenshots attached (that show the discrepency between our saved UID on the Prismic doc VS the UID that appears in the preview)
Hey team, are you rendering the correct page for the selected language?
Please note that to see the release version of a document, you need to have previews configured in your project.
Thank you for your reply Pau! We have identified what the issue was: our product slug was translated by mistake and we had to change it back to EN, it now works 
The thread can be closed 