When navigating to the Magento AMP Product page, users may see a whole webpage or extra blocks loaded inside AMP Iframe
Here is an example of this issue on Magento 2 AMP page frontend:
The issue happens when third-party extensions or themes modify product page layout and thus add additional content.
Go to your AMP Product page and open Iframe source in a new window:
Enable template path hints and find Magento blocks you want to delete in Iframe.
Go to your theme folder and create the following file:
Remove the extra blocks you found in step 2 using layout instructions.
Clear the Magento cache.
Now go back to your browser and refresh the AMP product page. The AMP Iframe should be displayed correctly.