There are many possible reasons why it will crash. Could be electrical, software application code or even the library itself. Since it is a STM32Duino port, the best place to get support will still be their github repository unless the issue is somehow related to the hardware module itself.
I am just thinking aloud. I am not sure what is the setup of your circuit. Actually, I feel that the electrical reason could be less likely the reason unless your circuit is surrounded by lots of EMI noises.
I find the STM32Duino for RAK811 a bit unstable. Honestly, I still have a pending issue with that and the LMIC port of MCCI. I can’t successfully join an OTAA before.
If it is FW related issue (STM32Duino), you need to do some test and have a repeatable fault. Else, it will be hard to fix it.