This works. I have been experiencing this in Portugal a lot lately, as there are many unnamed roads. I find the nearest address, enter it, then move the pin. It seems to allow the submission.
I try to do all my submissions from my laptop, and not the mobile device. I use the mobile only for the video uploads at the moment since I don’t know how to upload the videos from the laptop.
Regarding the issue with uploading video via PC or laptop, for the moment the feature is yet to be available. You may view video contributions of other Local Guides.
Please fell free to check out the instructions regarding the matter.