In case of a field with a cardinality >1, all videos are rendered inside the same video tag.
This is a good solution in case you want to upload the same video in different formats (mp4, webm etc) so the browser will choose the first source it supports.
But if you upload multiple different videos, current template does not work.
I attach a simple patch that fits our needs.
A more complete solution could be to add a settings into the field formatter to choose, in case of multiple videos, if they are different versions of the same video or are different videos to render separately