URL: https://www.pandora.com/station/play/2383756606496723654
Browser / Version: Firefox 56.0
Operating System: Mac OS X 10.12
Problem type: Something else - I'll add details below

Steps to Reproduce
(Nightly 2017-06-15)

1. https://www.pandora.com/
2. Log in
3. Create a "Station"; I selected "Barbershop Quartet Radio"
4. Listen to an entire song.
5. When the second song starts playing, the third song starts playing at the same time, leading to an unintentional mashup of the two songs.

Expected Behavior:
Only the second song plays

Actual Behavior:
Both the second and third songs play at the same time.

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