If there are elements on the page that don't appear in playback or on the heatmaps, there are several solutions you can try.
If the elements in question are loaded onto the page after the initial page has loaded, we might not pick it up automatically. This can be solved by setting a delay in your tracking code to configure when Mouseflow takes its snapshot of the page.
If this is the case, the issue is probably what we call 'double scripting'. A script from your website is being run in our playback window, overwriting the HTML that was originally recorded. Please open a ticket with the relevant details (link to affected recording, description of the content missing) and we can resolve this for you.