I have a wistrio rak5205 with the firmware compiled and flashed from the official github repo. I’m sending data obtained via serial in the wistrio through an esp32 board, but I have the same problem with the default application. The problem is that just after an hour it starts sending Lorawan packets every two minutes or so. Initially it sends data every 12 or 13 seconds, which seems to make sense considering that the duty cycle for eu868 is 1%. The payload is variable but never more than 19 bytes and I always send with SF12, so ToA aprox. 1318.9 ms this multiplied for 99 is equal aprox to 13s between packet sendings.
Diving through the code I found that in the RegionCommon.c file there is a RegionCommonCalcBackOff function, if I understood correctly, the backoff is used for lost packets retransmission, but apparently this function also affects the duty cycle for sending packets, the join with the gw is via abp, up to one hour there are no problems by sending every 13 seconds but after one hour the wistrio starts to give ERROR-6 (busy) until more than two minutes pass then gives its OK and repeats the behavior, if I set manually the return value of this function to 1 there is no further problems after one hour of running.
Thanks in advice