Difference in chips?

[THLL]

Hello I have noticed that some of the chips do not work like the others.

What is the difference between a NRF24L01+ 1420JB and NRF24L01+ 1405FJ

[Asbjørn]

We have seen several users here lately that have bought modules with counterfeit nRF24L01+ on them. They report that especially the Auto-ACK functionality is not working on the fake ones. May I ask you from where you got the various chips that you have and what kind of behavior you are seeing that's not according to your expectations?

[Asbjørn]

I'm sorry to say, but yes, these looks very much like the modules we have seen others use and the chip markings indicate that these are fake. Thank you very much for sharing the link, we want to stop the vendors of these modules. I would have to ask you to contact the vendor yourself and complain about the product that you receive isn't what was promised you.