Go to the BP_MasterBuildPart and Add the Set Collision Profile Name node and set the In Collision Profile Name value on that node to BlockAllDynamic like the image below shows. Then add the Set Collision Object Type node and set the Channel to BuildPart.

Also make sure that the Set Collision Enabled nodes highlighted in the image are set the No Collision.

Select the Destructible component and in the details panel make sure the collision settings are like the image below.