over mesh in instanced USD file cannot be rendered

**Describe the bug**

consider this usd file
```

#usda 1.0
(
defaultPrim = "item001"
metersPerUnit = 0.01
upAxis = "Y"
)

def Xform "item001" (
kind = "component"
)
{
def Xform "group001"
{
float3 xformOp:rotateXYZ = (19.0, 29.0, 42.0)
double3 xformOp:translate = (1.0, 1.0, 1.0)
uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ"]

def "geometry1" (
instanceable = true
prepend references =
)
{
}
}


}

over "InstanceSources"
{
def Xform "geometry"
{
def Xform "render_model"
{
def Mesh "model001"
{
# mesh data ...
}
}
}
}

```

And Another usd file
```

#usda 1.0
(
defaultPrim = "item001set"
metersPerUnit = 0.01
upAxis = "Y"
)

def Xform "item001set" (
kind = "assembly"
)
{

def Xform "item001AR" (
instanceable = true
prepend references = @ref first usd file@
)
{
float3 xformOp:rotateXYZ = (0, 0, 0)
float3 xformOp:scale = (1, 1, 1)
double3 xformOp:translate = (0, 0, 0)
float3 xformOp:translate:pivot = (0, 0, 0)
uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:translate:pivot", "xformOp:rotateXYZ", "xformOp:scale", "!invert!xformOp:translate:pivot"]
}

}
```

When I use arnold 7 aiStandin render this usd file.

The output render have no mesh rendered.

But when I set 'geometry1' instanceable as false in first usd file.

The final render will have the mesh rendered.

**Used Software Versions**
- Arnold Core: 7.1.2.0
- MtoA 5.1.3 427aec6e(fix-5.1.3) - May 20 2022 02:23:21
- OS: Windows
- Maya 2022

**Additional context**
I'm using arnold 7 And MtoA 5.1.3 with maya2022.

Start by reproducing the issue with the two provided USD files through Arnold 7.1.2.0 and the aiStandin path in MtoA 5.1.3. Compare rendering with geometry1 instanceable set to true and false; done means the instanced USD renders its mesh correctly with instanceable enabled.

Written by the indexing model from the issue text.