I have tried with mbed with different CE and CSN pins, but as the OP said, the port disappears when upload is finished. If I press the reset button twice to enter boot mode, the port reappears.
The problem does not seem to occur with any library other than NRFLite.
/*
nrF24 nrf52
CE -> D6 D0
CSN -> D7 D1 (SPI SS)
MOSI -> D10 (SPI MOSI)
MISO -> D9 (MISO)
SCK -> D8 (SPI SCK)
IRQ -> N.C
VCC -> 3V3
GND -> GND
*/
const static uint8_t PIN_RADIO_CE = 7; // D6
const static uint8_t PIN_RADIO_CSN = 8; // D7
/* OR*/
const static uint8_t PIN_RADIO_CE = 0; // D0
const static uint8_t PIN_RADIO_CSN = 1; // D1