Does Unburden's effect stack?

Question

For example, we have a Hawlucha with Unburden and someone who knows Switcheroo in a Double Battle. Hawlucha uses its Held Item, and Unburden activates. After that, the ally passes its ununsed item via Switcheroo. If the item passed by Switcheroo gets used, will Hawlucha's Speed rise?

Comments

Yeah, of course it does. It speed will rise twice.

Answer 1

This boost is lost if the Pokémon is switched out or gains a held item.

source
So in your situation, the Hawlucha's speed will double once, go back to normal, and then go back to double its speed when the item is lost the second time.