The missing code section of our diagnostics tool is referencing the floating trustmark code. This can happen with Shopify sites due to the content of the page being loaded dynamically. "Static Content" is unchanged or constant, while "Dynamic Content" is changing or lively. Static web pages contain the same prebuilt content each time the page is loaded, while the content of dynamic web pages can be generated on-the-fly.
In this case, some content is not generated for our crawler when it is indexing the site for search submission and diagnostics. No worries, as long as you have the McAfee SECURE app installed on your Shopify site the floating trustmark will continue to display.