Cannot use multiple SubScene tracks

Cannot use multiple SubScene tracks. When trying to add a subscene to a second subscene track, it just snaps onto the original subscene track.

1. Create a blank project
2. Create 3 Sequences in the Content Browser
3. Open Sequence 1 and create a Subscene track (also extend the playback range to 300 frames)
4. Add Sequence 2 to the Subscene Track
5. Create a second Subscene Track
6. Add Sequence 3 to the blank Subscene Track

Result: Sequence 3 goes into the same Subscene Track as Sequence 2.
Expected: Sequence 3 goes into the blank Subscene Track