Currently it is not possible to use batch release to warehouse function for order type subskription.

I you do it manually by warehouse management > Release to warehouse > Release to warehouse it works.

In warehouse management > Release to warehouse > Automatic release to warehouse there seems to be a fixed filter on order type "sales order" which cannot be deleted or changed to "subscription".

Idea is to modify this filter options in order to use Automatic Release functionality not only for sales orders but also for other order types.