Shane, I recreated the problem with the tegra_multimedia_api/argus/samples/multiSensor program!!!
The key was to run multiple of those executables. On our board we have 6 cameras. I rebuild that program three times and only changed the DEFAULT_CAMERA_INDEX value each time.
/samples/multiSensor/main.cpp
namespace ArgusSamples
{
// Constants.
static const uint32_t DEFAULT_CAPTURE_TIME = 600; // In seconds.
static const Size2D<uint32_t> PREVIEW_STREAM_SIZE(640, 480);
static const Rectangle<uint32_t> DEFAULT_WINDOW_RECT(0, 0, 640, 480);
static const uint32_t <u>DEFAULT_CAMERA_INDEX</u> = 4;
Program 1: DEFAULT_CAMERA_INDEX = 0
Program 2: DEFAULT_CAMERA_INDEX = 2
Program 3: DEFAULT_CAMERA_INDEX = 4
That gives me three programs with 6 total cameras.
I ran all of those simultaneously along with the stress program, and I get the same error result from Argus in syslog.