Why is SEQ= accepted on a command but ignored?
SEQ is not among the valid keywords/options for some commands (e.g., LJOB)
Keywords/options (like SEQ in this case) that exist for other commands are accepted by the LJOB command, but have no effect.
Basically you would only get an error if the Keyword/option does not exist at all or if you exceed the maximum length of its possible values.
Example : SEQ is a valid keyword (it can be used with commands like LPOST or LQ) and the maximum length of the accepted values for it is 5 digits (SEQ=SUBID when used with LPOST command). If you enter a command like LJOB,JOB=UARFE*,SEQ=SYS then SEQ is only validated for its length and since it is less than 5 digits, it is accepted but then ignored because it is not among the valid keywords/options for the LJOB command.
If you enter a command like LJOB,JOB=UARFE*,SEQ=SYS123 then you'll get an error:
SLI0-17 INVALID DATA FOUND FOR FOLLOWING FIELDS:
This is different with a command like LQ,JOB=UARFE*,SEQ=SYS where SEQ is a valid keyword for the command and is consequently validated either for its length and its value.
SEQ=SYS is invalid because for the LQ command, SEQ can only have values NATV - CA 7 - DLTM - DOTM - JOB