controller buttons/events don't work after pausing and unpausing scene

[ngokevin]

Description:

Blocks Inspector + Motion Capture work.

1. Enter VR. See controllers work when pressing buttons.
2. Open Inspector. Exit Inspector.
3. Enter VR again. Controller buttons do not work

• A-Frame Version: master/0.6.0
• Platform / Device: windows/vive
• Reproducible Code Snippet or URL:
  https://aframe.io/examples/showcase/tracked-controllers/