If the author is not shown in the actual output, then it won't show up there too.

I'm aware of the issue and in the next update it will be shown regardless of the "view" setting.

I just noticed we (wrongly) control author display based on the meta option for author display in Joomla's global configuration. I've removed this check and will push the change to K2 v2.10.3 (dev) in a while.

I've now uploaded the changes to K2 v2.10.3 (dev) which you can download from: getk2.org/downloads/?f=K2_Development_Release.zip

With this update, you won't need to display the user (author) in the item view. Since the data exists in the DB, it will just display in structured data.