Reproduction steps:
1. Open the attached project.
2. Build and run it as Standalone.
3. Click "Initialize Broadcast".
4. Click "Start Broadcasting".
5. Play the scene in the Editor (Do not close the Standalone Player).
6. Click "Initialize Broadcast".
7. Click "Listen for Broadcast".
8. Focus Standalone player.
9. Focus Editor.
- Console gets flooded with "host id out of bound id {0} max id should be greater 0 and less than {0}" error message

Reproduced with:
5.6.0f3, 2017.1.0b1

Not reproducible with:
5.5.3p1