My knowledge in source is not so good [im an Engeneer, goddammit xD] but I'll try to help using logic. I don't know if it's right. Here we go!
You declare output[CHAT_SIZE_MAX] with char and then uses it to store base and job level, which is int64 (I guess) in sprintf:
I suggest you declare another variable int64 and store those in another line like:
int64 output2[CHAT_SIZE_MAX];
sprintf(output2, "Lvl: %d/%d",pl_sd->status.base_level, pl_sd->status.job_level);
and let the first line like this:
sprintf(output, "Name: %s | Job: %s", pl_sd->status.name, job_name(pl_sd->status.class_));
I never did this before. Sorry if I'm wrong.
Good Luck!!