Add-webhook on deep mutations

No. For example, if you have a schema like:

type Author @lambdaOnMutate(add: true) {
  ...
  posts: [Post]
}

type Post @lambdaOnMutate(add: true) {
  ...
  author: Author @hasInverse(field: posts)
}

and you are doing an addAuthor with nested posts, then the webhook registered for Author.add will be triggered, not the one on Post.add. The Author.add webhook will get an event that contains the input that addAuthor received, including the nested posts.

If Author.add isn’t getting triggered, then it might be a bug.