Hello - I am having problems pinging multiple T4.1s on the same network via UDP and the OSC library from CNMAT.

I have simplified my sketch to only include the UDP/OSC comms between two T4.1s and host computer. It appears that the Udp.parsepacket() function performs as expected for one T4.1 on the network while the other device doesn't read any data at the udp.parsepacket() call. Whichever device was flashed last is the one that is communicating without problems.

I'm wondering if there's something obvious I'm missing or if others can reproduce this scenario.

I'm using Touchdesigner to send and receive OSC, but have also tested with Max/MSP with the same results. The T4.1s and host computer are the only devices connected to the network.

General setup:
MacBookPro, OS 10.14.6
Touchdesigner 099, build 2020.22080
Max/MSP, v8.1.5
Teensyduino 1.53 & 1.54 beta #3
Netgear GS305 network switch

Code:
#include <NativeEthernet.h>
#include <NativeEthernetUdp.h>
#include <OSCBundle.h>

// ETHERNET STUFF
EthernetUDP Udp;
OSCBundle bndl_ping;
IPAddress hostIP(10, 0, 1, 65);       // HOST IP

IPAddress teensyIP(10, 0, 1, 201);    // Teensy #1 IP address
int localPort = 9011;                 // Teensy #1 local port
int hostPort = 9001;                  // Teensy #1 host port

//IPAddress teensyIP(10, 0, 1, 202);  // Teensy #2 IP address
//int localPort = 9012;               // Teensy #2 local port
//int hostPort = 9002;                // Teensy #2 host port

int size;

// MAC ADDRESS
#if defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MKL26Z64__)
static byte mac[6];
void read(uint8_t word, uint8_t *mac, uint8_t offset) {
  * FTFL_FCCOB0 = 0x41; * * * * * * // Selects the READONCE command
  * FTFL_FCCOB1 = word; * * * * * * // read the given word of read once area

  * // launch command and wait until complete
  * FTFL_FSTAT = FTFL_FSTAT_CCIF;
  * while (!(FTFL_FSTAT & FTFL_FSTAT_CCIF));

  * *(mac + offset) = * FTFL_FCCOB5; * * *    // collect only the top three bytes,
  * *(mac + offset + 1) = FTFL_FCCOB6; * * *  // in the right orientation (big endian).
  * *(mac + offset + 2) = FTFL_FCCOB7; * * *  // Skip FTFL_FCCOB4 as it's always 0.
}
void read_mac() {
  * read(0xe, mac, 0);
  * read(0xf, mac, 3);
}
#else
void read_mac() {}
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
#endif

void setup()
{
  delay(1000);
  
  // SERIAL
  Serial.begin(115200);

  // UDP STUFF
  Ethernet.begin(mac, teensyIP);
  Udp.begin(localPort);
  Serial.println("teensy has arrived");
}

void loop()
{

  OSCBundle bndlReceived;
  
  // receive a bundle
  if ( (size = Udp.parsePacket()) > 0)
  {
    Serial.print("bundle size: ");
    Serial.println(size);

    while (size--)
      bndlReceived.fill(Udp.read());

    if (!bndlReceived.hasError())
    { 
      if (bndlReceived.size() > 0)
      {
        bndlReceived.dispatch("/ping", ping);
        
      }
    }
  }
}

void ping(OSCMessage &msg)
{
    Serial.println("ping requested");
    
    bndl_ping.add("/pingReceived ");
    Udp.beginPacket(hostIP, hostPort);
    bndl_ping.send(Udp);
    Udp.endPacket();
    bndl_ping.empty();
}