When a job runs in the console log for that job 'p4 changes -m1' is run for every branch that matches the multibranch project source. For example the following job is running for '//streams/main':

p4 client -i 
Client  jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b saved.(p4):stop:8
(p4):cmd:
...   View:
      //depot/multibranch/dev1/Jenkinsfile //jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b/Jenkinsfile

p4 client -i 
Client jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b saved.(p4):stop:17
(p4):cmd:
...   View:
      //depot/multibranch/dev2/Jenkinsfile //jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b/Jenkinsfile

p4 client -i 
Client jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b saved.(p4):stop:26
(p4):cmd:
...   View:
      //depot/multibranch/main/Jenkinsfile //jenkinsTemp-c31cbc7b-5563-4c2e-96e4-60fc95703f4b/Jenkinsfile

Note that clients are created for 'dev1', 'dev2' and 'main' even though we only need to probe for changes to 'main' in this job execution. (Full console log attached)

I would expect this in the Multibranch Scan Log but not every job execution.

Reproduction steps:

(1) Create following folders in Perforce and submit a Jenkinsfile to each:

//depot/multibranch/dev1/...

//depot/multibranch/dev2/...

//depot/multibranch/main/...

(2) Create a multibranch project with Helix Branches as the source and 'include branches' set to:

//depot/multibranch/...

and Scan Multibranch triggers set to '5 minutes'.

(3) Manually build each job.

(4) Submit a new file to '//depot/multibranch/main/...'.

(5) Manually build the job. See that all branches are scanned in the console log for the main build job.

(6) Submit another new file to '//depot/multibranch/main/...'.

(7) Wait 5 minutes. See that all branches are scanned in the console.log and the Multibranch scan log.