The availability and whether "Publish incl. subpages"  is really triggered seems a bit shaky.
It may work in many cases. But in many cases also not.
Below 2 examples to reproduce.

 Action not available

The action Publish incl. subpages not available.

To reproduce

• Create a new little subtree of pages: /a/b/c
• Select the page a
  • Publish incl. subpages is not available

In this case, you must publish each and every page separately.

Action effectively with no effect

Use the subtree from above. Before doing anything else, publish /a and /a/b each separately.

To reproduce

• Edit both /a and /a/b
• Select page /a
• Action Publish incl. subpages is now available,
  • click it

=> Nothing happens. Nothing in the log. 
You can check the pages on the public instance.
(Interestingly, as sadly as it is that Publish incl. subpages has no effect. On this stage one can use (again) Publish separately for each page, which works.)