We use github-branch-source-plugin to detect changes.
Getting remote branch master...
[Tue Nov 05 11:54:53 EST 2019] Received Push event to branch master in repository org/repo UPDATED event from 126.96.36.199 ⇒ https:11:54:53 Connecting to https: Checking branch master
Getting remote pull requests from branch master...
Changes detected: master (OLD-SHA → NEXT-SHA)
This is what triggered the build.
I checked github and confirmed, this is a single commit.
Actual result: Both classic and blueocean show 1024 changes listed for the build instead of the expected single commit (NEXT-SHA).