This is basically the same issue as https://www.drupal.org/node/807126 that was filed against the D6 branch of ImageField. That issue was closed as "fixed" by @quicksketch by pointing to the ImageField Tokens module:

Now with Tokens in core, it makes sense to take advantage of them and use them where possible.
PS: should support transliteration once in core (#904)
PR by @BWPanda: https://github.com/backdrop/backdrop/pull/3068
Recent comments
@yorkshirepudding, In the end I fixed it by deleting the config/active folder contents, copying the config/staging/ files into config/active, importing the database again and clearing the caches...
Importing the staged config throws an error: another field with the same name already exists
Thanks, I have to go out now, I will try later on and report back
Importing the staged config throws an error: another field with the same name already exists
Hi Francis. Yes, what config do you have in staging for it? You might have configs like: field.field.field_video_embed field.instance.node.page....
Importing the staged config throws an error: another field with the same name already exists