We observed that using the same asset for both the video and portraitVideo src properties of @react-visual/contentful resulted in no video loading at one of the breakpoints. Maybe there is some issue with both responsive sources having the same URL?
Regardless, I think a good solve could be to add some deduping, maybe in packages/react/src/LazyVideo/LazyVideoServer.tsx, that filters out duplicates for both image and video.