Heres a video showing how it should work and how it works; videoshowingerror - YouTube
0.00-0.12 - How one would expect it to work if the box were attached to the platform.
0.13-0.28 - How it behaves when it is attached to the platform.
Now only the player can trigger the events in the blueprint in the video. It does not matter how big the trigger box is. The moment the player touches that platform both events are fired.