I don't remember what I ate last night
but I can spout off obscure rules to all sorts of games like nobody's business!
We'd like to Produce Supplies using the system-wide production option. Doing so would nominally place N cubes (11 in our case) in havens and supply centers, but there are <N cubes (10 in our case) in the stockpile.
Our reading of Using Abilities (rulebook p11 "You must be able to use all of an ability in order to activate it.") indicates that we cannot, therefore, take this action at this time.
True? Kinda hoping we're wrong, but...
On page 10, where it describes the action it says:
If there aren’t enough Supply cubes in the stockpile to
fill locations to their populations, put as many as you can
in any order you like.