U1 music player can not go back a track unless the player is playing

Description:
If you select an album let it play until it stops at the end you can not hit the back button (the one to the left of the play button) to get back to the first track.

Service:
U1 Music player
https://one.ubuntu.com/music/player/

Steps:
1. Goto the link above (login if necessary)
2. Select an album to listen too
3. Click on play tracks
4. Play the album to the end
5. Hit the back button to the left of the play button on the player to get back to the first track

6. Press play so the last track plays
7. Now hit the back button

8. Get mid way through the album and hit pause
9. Now hit the back button

Expected Results:
I expect to see happen what happens with steps 6-7 or 8-9 ie the player has stopped but I can go back a track

Actual Results:
If you follow steps 1-5 you will note that the player will stay on the last track and not got back at all.