Hello. Please make in this order
1) add link to any video
2) delete (erase) description first (make it empty)
3) then edit title
4) Press “Share” button.
Result: text “Enter some description for the video” saved as video’s description.

Video: https://www.dropbox.com/s/jytwncly4g3hy1b/%D0%92%D0%B8%D0%B4%D0%B5%D0%BE%2017.05.2019%2C%201%2006%2014.mp4?dl=0

Thanks.