Hi, I had the same issue and I solved it this way:
1 Go to poject settings and then to collisions. Create a new preset with this settings:
Then on a BP with the object you want to fracture go to the Geometry Collection settings and sarch for “Collision Profile Per Level”. Use the new preset you’ve created for the index 1 and 2.
Now you should be able to collide with the object but not with it’s fragments after fractured.