We use CloudBees-2.138.2.2 Jenkins and have had lot of challenges to trigger jenkins jobs only based on commits in our Github repo. I am still looking for the exact working script for scripted pipeline and not declarative one.
so For example :- pipelineTriggers([cron('0-59/2 * * * *')]), works but pipelineTriggers([pollSCM('0-59/2 * * * *')]), never works despite new commits