Works fine in Damus and directly viewing it in any browser, must be how you pasted it in Iris? Or something with Iris?
That's what it looks like in the browser in Iris for me.
This is the link: https://nostr.build/av/nostr.build_8a15edf8988793fea3c5dd656a96f27cc65e9b9380776015af4cb3f3df317405.mov
Discussion
Yeah it works fine for me in Damus as well. Have seen this happening on other people’s videos as well when viewing on Iris in the browser. 🤷♂️