Harmony Configured SPI Receive Always Returns 0 (AnotherEngineer)

I've used the MPLAB Harmony Configurator to setup SERCOM6 as SPI on an ATSAME54P20A. Whenever I use the following Harmony API to send/receive: SERCOM6_SPI_WriteRead(&txBuffer, txSize, &rxBuffer, rxSize); The receive buffer always returns all 0's. ..