My developer is pushing the code in Dev branch of Bitbucket but in Jenkins it triggers Dev, Test, Stage and Prod pipeline though there is no changes deployed in Other branches and it simply redeploys the last commit in Test, Stage and Prod. But then why should any code push to DEV branch should trigger another pipelines.

Please note that every env pipeline is only checking out respective env branch for deployment. I had raised this issue with Bitbucket community as well but they confirmed that no issues seen from Bitbucket end and suggested to check from Jenkins end.

In my jenkins every pipeline is triggered based on "Build whenever a change is pushed to Bitbucket"