IsOverlappingActor is always returning false

When you use the IsOverlappingActor node to determine whether or not something is overlapping another actor, it returns false regardless of whether or not you're actually overlapping another actor.

Reproduced in 4.8.3, 4.9.1 and Main CL: 2700641.

1. Open attached project (Overlapping Actor Test)
2. Drag Testing Overlapping into the level.
3. Click the floor and ensure Generate Overlap Events is checked
4. Move the collision you just placed into the level so that it is colliding with the floor.
5. PIE
6. Press the L key, which will fire off the IsOverlappingActor test.

Result: IsOverlappingActor returns false, even though the collision is overlapping the floor.

Expected: IsOverlappingActor would return true.