3.3.0 heightfield crash!

Hi, everyone.

My my program use multiple material heighfield.
But, simulate in crash. (random)

std::vector<PxHeightFieldSample> samples(num_samples);
for(; ; )
{
    // blah, blah..
    samples[i].height = height;
    samples[i].materialIndex0 = mtrl_idx;
    samples[i].materialIndex1 = mtrl_idx;
}

PxHeightFieldDesc desc;
//blah, blah..
desc.samles.data = samples.data();
desc.sampes.stride = sizeof(PxHeightFieldSample);

PxHeightField* height_field = PHYSICS.createHeightField(desc);
PxRigidStatic* actor = PHYSICS.createRigidStatic(PxTransform(PxIdentity));

// attention!!
PxHeightFieldGeometry geometry(height_field, PxMeshGeometryFlags(PxEmpty), 1.0f, 1.0f, 1.0f);
std::vector<PxMaterial*> mtrls(4, default_mtrl);
PxShape* shape = actor->createShape(geometry, mtrls.data(), 4);

//blah, blah..

No crash in use single material.
How can i fix it?

Sorry, my bad english.