How to define a Volume in a plugin?

I’m trying to make a plugin and I wanted to have a custom Volume that comes with it. However when you drag the volume into the world, the ABrush::UModel::Brush and ABrush::UBrushBuilder::BrushBuilder are both null after they’ve been fully constructed.

After doing some debugging, the best reason I’ve been able to find is that this line will fail
IsChildOf( AVolume::StaticClass() )
I assume it is because a class defined in a plugin is invalid for this call. Do you have any suggestions for what I can do to get around this issue OR should this be logged as a bug?

bool UActorFactoryBoxVolume::CanCreateActorFrom( const FAssetData& AssetData, FText& OutErrorMsg )
{
    if ( UActorFactory::CanCreateActorFrom( AssetData, OutErrorMsg ) )
    {
        return true;
    }

    // this line fails
    if ( AssetData.IsValid() && !AssetData.GetClass()->IsChildOf( AVolume::StaticClass() ) )
    {
        return false;
    }

    return true;
}

Just to be clear, everything works correctly if I place the class in the project root, but not if I place the class in a plugin.