Mogaraghu:
SO it ultimately looks like if I have a RFID reader and RF24 on the same SPI bus, the RF24 has to be only a Tx unit as otherwise it has to be listening always and we have a issue.
That does not make any sense.
When you have more than one device on the SPI bus your program must manage which device is selected before you try to communicate on the bus. In the case of the nRF24 that is with the CSN pin. It is probably the RfidSel pin for the RFID reader. At any one time no more than one of them should be selected - I think that means HIGH, but you should check.
I see no code in your program to change the value on those pins
The nRF24 will listen and receive a message even if CSN is not selected
...R