either there is a hierarchy in which one Resource is always used before another when 2 or more Resources are on the same Build, either the first or last Resource placed on a Build is used, or it depends on which items the Resources are placed on if 2 or more Resources are used.
there could be a few more criteria to determine which Resource is used, but the bottom line is that only one resource can be used. putting 2 or more Resources on your Equipment is like putting a Set on your Equipment that can’t be activated. using a Reactor Set when you don’t have Orb Skill on your MH or Orb Proc for example.
here was an idea I had for using multiple Resources. the thing is, some of the Resources just wouldn’t work with other Resources, which is why only one Resource per set of Equipment.