Events on frame 0 fire twice

Regression - does not occur in 4.13.2 or 4.14.3

Does occur in Dev-Sequencer

1. Create a Level Sequence with an Event Track
2. Add a key at frame 0
3. Right click that key and set the Event Name to TestEvent
4. Alt-Drag the key to frame 50, this will duplicate it
5. Save the Level Sequence and drag an instance of it into your level
6. Select the instance in level and set Auto Play to true
7. Open up the Level Blueprint
8. Right click inside the BP graph and search for Custom Event, then click it to create one
9. Rename the custom event to TestEvent
10. Drag off the exec pin and create a Print String node
11. Set the In String to TestEvent Fired
12. Compile the level BP
13. PIE

Result: Observe that TestEvent is fired three times - twice on frame 0 and once on frame 50

Expected: TestEvent to only fire once