Similar to https://issues.jenkins-ci.org/browse/JENKINS-50168 and https://issues.jenkins-ci.org/browse/JENKINS-27327 BUT both of those tickets got distracted with the parameterized branch name, while the polling branch issue I think is distinct.
Problem:
When using pollscm in a pipeline job, the plugin will always poll with the branch that was configured on the last job run.
Reproduction steps: