AutoComplete Rule with DFF and Business Unit

Hi,

I am trying to add an Autocomplete rule where Assignment DFF is defaulted based on Business Unit. So far, the logic is working but partial trigger is not working. I followed the steps on this event, but I couldn't find the Business Unit ID and the Business Unit in Page Composer does not have Auto Submit option.

For example, when the Business Unit is filled in Change Assignment, the value on DFF Attribute 6 and 7 does not update (even though it is on the back end), meaning, I have to go to next step and go back to the Assignment page to visually see Attribute 6 and 7 updated.