Hi all,
Just filing this as a bug - I couldn't see any other bugs reported on it.
In the iOS app, when you upload a video (at least a video taken using the iPhone's camera and the default app), the default copyright string set in the app's settings is not added in.
This is added in fine for images, and for videos imported using Lightroom CC on macOS.
I've tested this on two completely different iPhone XS devices and the results are the same.
Cheers,
Nick