This page contains a list of known issues associated with Stream Migration Actions and updating Embed Codes for Microsoft Stream Videos.
...
Prior to February 15th 2025, you can use the Watch in Stream button to open the migrated video, and manually update the embed code.
After February 15th 2025After 15th February, the “Watch in Stream” button may not function (or the embed may not display at all), so you will not be able to locate the migrated video.
...