This is an inconsistent bug with the chrome browser and not something we can resolve in the theme unfortunately. Please see the following bug report:
Server-side caching can exacerbate this issue. We recommend using WordPress plugins to manage caching instead of cloudflare or similar services on the host, such as W3 Total Cache with Browser and Database caching enabled (do not enable page caching or minify)
Please also update your theme under Theme Options > Update just to ensure you have all the latest features. It won’t fix this from happening sometimes but it will improve overall performance.
As a workaround, we recommend using oEmbed and enabling the Thumbnails in your widgets and index pages so the page is not loading iframe data from the cache when hitting the back button.