Why would a call to libconfig's config_lookup function end the program?

Question

I am using the very nice libconfig library, made by Mark Lindner. It is available as part of a Red Hat installation.

Sometimes, when I called config_lookup the call doesn't return. Most times it does.

Instead, the process stops running, and our watchdog script notices that it has stopped running and restarts it.

The output and the code is below. Is this a known behavior of config_lookup?

08/11/2020 17:54:37: debug - before call to config_lookup
08/11/2020 17:55:05: Started:          Tue Aug 11 17:55:05 2020

    int               i;
    int               sapfco_length;
    config_setting_t* sapfco;

    LogMessageLevel(4, "debug - before call to config_lookup");

    sapfco = config_lookup(&cfg, "sponsors_and_programs_for_cat_outbound");

    LogMessageLevel(4, "debug - *after* call to config_lookup");
    LogMessageLevel(4, "debug - sapfco = 0x%8.8x", sapfco);