Is it happening with all multipage projects? Did you try after clearing the cache/cookies of the browser to check if that makes any difference? Which browser are you using? What export option were you using (JPG, PDF, or PNG) for export?
I tried downloading multiple-page projects in all formats, and it worked fine for me.
Can you share a screenshot of the exported project and, if possible, a screen recording of the workflow you followed with the incorrect exported file? This will help us in investigating the issue.