In MC, the execution cluster assigns forwarded jobs with different job IDs from the submission cluster. You can use the local job ID or src_job_id@src_cluster_name to query the job (for example, bjobs 123@submission_cluster_name).
The advantage of using src_job_id@src_cluster_name instead of a local job ID in the execution cluster is that you do not have to know the local job ID in the execution cluster. The bjobs output is identical no matter which job ID you use (local job ID or src_job_id@src_cluster_name).