SPS.updateParticleVertex Gives Vertex Undefined Error in 4.0.0.18

@jerome

var myVertexFunction = function (particle, vertex, i) {
......
}

 SPS.updateParticleVertex = myVertexFunction;

Line 41 in this PG gives vertex undefined error https://www.babylonjs-playground.com/#1X7SUN#5

OK in stable https://www.babylonjs-playground.com/indexStable.html#1X7SUN#5

Pinging @sebavan as this could be related to modules

Ok found it will be fixed ASAP