If your permission is set to "always ask", you will get a message when something is trying to pull from you.
That message won't re-appear when it should if you do it in a particular order.
-> undocking/redocking to one of the unload rails of the same entity, will not trigger it asking again when it should.
If you dock to another ship's unload rail, it will ask for that ship, and also if you then dock back to the previous entity. But that seems to be the thing you need to do then, you have to trigger a pull permission on another entity in order to get it asked again for the one you already had it for.