I am trying to use the Supply Method "If unavailable, trigger another rule" in a route in Odoo V13.

The goal was to create a pick from a sales order, but when the pick location (wh/stock/pick) is empty, it should be picked from a different location in my warehouse (wh/stock/bulk).

I have added this route to my normal "pick" (standard Odoo for 2 step deliveries).

And after that, I have added another rule, an internal transfer, from the different location (wh/stock/bulk) to the pick location (wh/stock/pick). Here I have added the supply method "Take from Stock". 

The result is that an extra step is added to the delivery process (Internal, pick, ship).  This is always, meaning it works exactly the same as the supply method "trigger another rule", i.e. it doesn't take into account the stock in the location wh/stock/pick and the internal transfer is always created. And you are not able to pick the product from the pick location (wh/stock/pick), because it needs to be on the (wh/stock/bulk) location.

I see that this is being used in standard MTO routes from Odoo, but here also, the available stock is always skipped.

Is it possible that this supply method "If unavailable, trigger another rule", is not working as expected?

If not, what is the goal of this supply method? How can I make this work?