Only notebooks and tasks which are within the Gneo Stack in Evernote will sync to Gneo.
If you wish to move an entire notebook into the Gneo Stack, the sync is designed so that not all of your Evernote notes will sync to Gneo as these may not all be tasks and syncing all of these many notes may slow down the Evernote sync.
Therefore, if you drag an entire Notebook from outside of the Gneo Stack into the Gneo Stack, only the Notebook, not the tasks, will be synced to Gneo.
If you also wish to move the tasks, you can either move individual tasks into a notebook within the Gneo Stack - these tasks will then sync to Gneo.
Another option is to move the notebook into the Gneo Stack and make a small amend to each of the notes in the notebook, for example, add a 'space' after the note title. This will sync the tasks to Gneo.
If you have many tasks in the notebook on Evernote which you wish you move into the Gneo Stack, as a workaround you can move your tasks into another Notebook in the Gneo Stack and then back into the correct Notebook and they will then sync to Gneo.