In the docs, it says the following:
The LocationsForMove resource represents the locations that a fulfillment order can potentially move to.
How does Shopify actually determine if a fulfillment order can be moved to a different location?
I recently had an order move from one location to another location (my location) even though my location doesn't have one of the SKUs. The order had two items. One item is stocked by my location (and another location) but the other item is not stocked by my location.
I used Shopify API's LocationsForMove.
I've connected with our internal dev teams who work on fulfilment and locations and they confirmed we don't allow fulfillment orders to move to locations where the items are not already stocked. To investigate this, you'll need to contact support who will be able to analyse this specific order number and determine why this has happened.
Hope this helps!