Hey @Guaby
This is a known issue when links are automated into a video field. In order for the video link to process, click in at the end of the url, add a space, delete the space, and then press tab.
If that sounds tedious 
then I suggest using my preferred method of relying on the Youtube ID. I’ll still import the video field url as a reference too.
Then in the Designer use an embed instead of the video element. Here I am pulling in the Youtube ID dynamically for each video. This also gives you more control over the embed if you want to use some of the customization options provided by YT.
I’d suggest implementing the Youtube Lazy Load technique which is what you see in my example.
Hope this helps. Cheers.