I wasn't able to locate it in a few minutes of searching, sorry. Youtube's search pollution problem for popular topics is really bad.

Edit: Here's an article[1] that seems to have the video embedded, with a link to the annotation.

[1] https://foxtrotalpha.jalopnik.com/video-analysis-of-trident-...

It might be here [1].

Around 5:00 minutes, the vehicle seems to shed smaller objects.

https://www.youtube.com/watch?v=cc0_wZat4nI

Maybe this?

https://www.space.com/31122-trident-missile-test-photos-vide...