Enabling Flex loses audio signal.

Scenario:

Create new project. Create 1 new audio track. Import an audio file to Project pane. Drag audio file to track. Plays normally. Then, I engage Flex Pitch on that track at which point I no longer hear audio. Even when I open the audio file in the track audio editor below. It's playing but I hear no audio. If I go back to the track and remove Flex Pitch, I hear the audio again.

An I doing something wrong, or is this an El Capitan/Logic Pro X bug?

iMac Late 2012

El Capitan 10.11

Logic Pro X 10.2.0