Yuumi's passive is badly worded.
It says that if she is attached when she used her passive her ally will get the shield, it should say if she attaches after using her passive, since she can't proc passive while attached.
It says that if she is attached when she used her passive her ally will get the shield, it should say if she attaches after using her passive, since she can't proc passive while attached.
It's pretty confusing yes.