GPUParticleSystem error when scene check isReady

Hello!

I updated new version 3.2.0-alphaC and get an error with GPUParticleSystem.isReady(). 
Cause of this is when scene check isReady, it call GPS.isReady() but GPS not render at the moment. Means, _updateEffect and _renderEffect attribute undefined.

See console: http://www.babylonjs-playground.com/#9RSEFL