Vidyard Video Hubs have the ability to be customized using either the tools that are shown in the editor or via HTML and CSS code.
You have a background image in your CSS that appears after the page has fully loaded. However, you notice that another image is loading before your background image and it causes a visual problem. You cannot find any reference to this image in the code.
This issue is likely due to having selected a background image using the upload tool, but there is also a reference to a background image within the code.
You can use the Reset background to default tool found in the top right corner of the video hub when in design mode. It's likely that this set of tools were used to originally upload the image. Once it's been removed, you can use the CSS version if preferred.