Ok, I think you are actually overwriting them.
If you have this sort of struct
and a MAP like this ( not an array ). You’re using a map, but calling it an array 
I can talk to one of the faces with the actual ‘set members in struct’ node ( you just have a function with the same name )
This will set the forwards element to false without touching the other three ( because it’s the only one showing on the node )