When working with multicore applications, you need to specify the database configuration for each domain to properly decode the logs.
The following example command uses database configurations for multiple cores:
nrfutil trace stm --input-file stm_trace.bin --database-config 0x21:build/my_app/zephyr/log_dictionary.json,0x22:build/my_app/zephyr/log_dictionary.json --output-ascii decoded_multicore_trace.txt