The passive check result submitted by check_by_ssh to
the external command file should have square brackets
around the timestamp.
Fix by changing line 135 of check_by_ssh.c from:
fprintf(fp,"%d
PROCESS_SERVICE_CHECK_RESULT;%s;%s;%d;%s\n",(int)local_time,host_shortname,srvc_desc,cresult,output);
to:
fprintf(fp,"[%d]
PROCESS_SERVICE_CHECK_RESULT;%s;%s;%d;%s\n",(int)local_time,host_shortname,srvc_desc,cresult,output);