868.1 MHz not working, 868.3 Mhz & 868.5 Mhz fine

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trafficstars

I have a dual channel gateway. Thus, i can configure two channels in parallel. I configured 868.3 MHz on one radio module and 868.1 Mhz on the other. OTAA worked on 868.3 MHz everytime. I switched the configuration between both modules and ... still 868.3MHz working and non success on 868.1 MHz.

After that, I decided to force the Join process on one unique frequency by modifying the lorabase.h file.

enum { EU868_F1 = 868300000,      // g1   SF7-12
       EU868_F2 = 868300000,      // g1   SF7-12 FSK SF7/250
       EU868_F3 = 868300000,      // g1   SF7-12
       EU868_F4 = 868850000,      // g2   SF7-12
       EU868_F5 = 869050000,      // g2   SF7-12
       EU868_F6 = 869525000,      // g3   SF7-12
       EU868_J4 = 864100000,      // g2   SF7-12  used during join
       EU868_J5 = 864300000,      // g2   SF7-12   ditto
       EU868_J6 = 864500000,      // g2   SF7-12   ditto

The OTAA is using the three first frequency set. So I set them to 868.3 MHz and it worked on the first TX. Then I set them to 868.1 MHz and it never worked. Then I set them to 868.5 MHz and it worked on the first TX.

Do you have any idea where does that behavior could be coming from? I setup my gateway on LoraServer to receive any TX from default channels 0, 1 and 2 (868.1 MHz, 868.3 MHz and 868.5 MHz)