I'm using the nrf9160dk (ns). I started an application based on the SIMPLE_MQTT sample. At first, every this worked. I added my one MQTT client with a different set of buffers and structures.
The "original" MQTT client (the one that runs from main.c) is working well. When I try to create 2nd client from a different thread, (and the LTE is connected), once I get to nrf_getaddrinfo the system reboot itself.
Following is the code that eventually calls to nrf_getaddrinfo. (the same nrf_getaddrinfo worked fine when called from main)