FYI - YouTube unilaterally moved the watermark [grumble]
They moved it to the bottom right now. It used to be the top right. So if you sometimes altered the positions of things in your video like labels, captions, annotations, or even images with that in mind, they've now messed things up for you. Thanks, YouTube. And *thanks* for not simply giving us an option of where to put it.
"Branding watermarks now appear on the bottom right, so they can be used together with cards."