When one prepares a project as a local project in Studio with the intention to save it to the cloud afterwards (this is the current workaround for being able to edit the source documents before they go into translation), it is not possible to do a pretranslate using cloud-based TMs (translation engine).
The function is available and can be triggered, but it doesn't do anything.
This is required for the PM to properly prepare the documents before they go into the translation phase.