Sorry for my NRF24 clone post yesterday. The ACK bit was an issue with the NRF5 platform. I had switched the memory region to handle TX/RX/ACK packages separately. Sometimes the received packages are written in the wrong region. I had seen my testing ACK bit. Now, I have changed my NRF5 code and I can't see no difference between the modules, I have. ACK and timing are exactly at the same level.