Async Usart IO_READ always null SAMD20J16 - c

Question

Fairly new to the Atmel software framework, usually use MPLab/PIC devices but for my project I needed to build a UART router capable of connecting 6 UART devices together so I chose a SAMD20J16 chip. So far iv'e configured the drivers using ATMEL start with USART HAL_ASYNC drivers for all USART modules.
Iv'e gotten the device to write to all 6 USART modules and have gotten the read interrupt to trigger but I am unable to read from the usart buffer. For now ive stripped it down to the minimal code possible to try and find out why it's not working, it's probably a simple oversight on my part, but Iv'e been searching the internet for 2 days and all the documentation I can find using the HAL_ASYNC drivers in ASF4 is flaky at best.
#include <atmel_start.h>
int main(void)
{
int nRead=0;
uint8_t rxPData;
/* Initializes MCU, drivers and middleware */
atmel_start_init();
//DECLARE UART STRUCTURTES
struct io_descriptor *uartD1;
usart_async_get_io_descriptor(&USART_0, &uartD1);
usart_async_enable(&USART_0);
struct io_descriptor *uartP;
usart_async_get_io_descriptor(&USART_1, &uartP);
usart_async_enable(&USART_1);
struct io_descriptor *uartD3;
usart_async_get_io_descriptor(&USART_2, &uartD3);
usart_async_enable(&USART_2);
struct io_descriptor *uartD4;
usart_async_get_io_descriptor(&USART_3, &uartD4);
usart_async_enable(&USART_3);
struct io_descriptor *uartS;
usart_async_get_io_descriptor(&USART_4, &uartS);
usart_async_enable(&USART_4);
struct io_descriptor *uartD2;io_write(uartP, (uint8_t *) "UART P\r\n", 8);
usart_async_get_io_descriptor(&USART_5, &uartD2);
usart_async_enable(&USART_5);
void uartP_callback(const struct usart_async_descriptor *const io_descriptor){
if(usart_async_is_rx_not_empty(uartP)){
io_write(uartP, (uint8_t *) "TEST P\r\n", 8);
nRead=io_read(uartP,&rxPData,6);
io_write(uartP,&rxPData,nRead);
}
}
usart_async_register_callback(&USART_1, USART_ASYNC_RXC_CB, uartP_callback);
while (1) {
}
}
Right now the observed behavior is anytime I send a UART packet it triggers the interrupt, and passes the IF rx_buffer_is_not_empty and sends back "TEST P\r\n". I added this line of code after some testing just to see if the interrupt was triggering.
However, no matter what input size i send to it it never transmits back any data that was sent to it.
Right now i'm simply trying to verify that I can receive and transmit on all usart ports, the final code won't have transmits inside the receive interrupts.