Adding array element of instanced meshes during simulation does not increase amount of elements in array

Adding array element of instanced meshes during simulation does not increase amount of elements in array.

Regression (No) issue (does) occur in 4.10.4

(Note: Step 7 is not necessary, the issue will occur outside of simulation as well.)

1. Open Editor (QAGame)
2. Create new actor blueprint
3. In new actor blueprint, add instance mesh component
4. Set instance mesh static mesh component to Barrel_02
5. Compile
6. Add a copy of new actor blueprint to level
7. Press Simulate
8 Select new actor blueprint in level viewport while simulation is running
9. Select InstancedStaticMesh in details pane
10. Press '+' next to Instances>Instances>elements

Results
No elements are added

Expected
Element is added to instance array.