Highlighted Content with New Stream - Displaying Thumbnails

Hello Community!

I am looking to create a video archive that is using the new 365 Stream experience. It was https://learn.microsoft.com/en-us/stream/streamnew/portals-guide-training-site#videos-grouped-by-categories to use the Highlighted Content web part to display the videos. But, I am struggling to get the thumbnails to properly display. 

I have https://support.microsoft.com/en-us/office/include-a-custom-thumbnail-for-your-video-or-audio-file-with-stream-on-sharepoint-b24f6c73-6496-44d4-bb31-bc0be3e61425 in the new Stream using the Video Settings but it does not reflect that in the Highlighted Content web part when I am in the Filmstrip, Grid or Compact views (which all display thumbnails). But, it works in the Carousel view - so I know that the thumbnail was properly added. 

What am I missing? I want the SharePoint site to look professional as they browse through multiple videos but I can't seem to get the thumbnails to display properly.