The built in Verify Committer pre-receive hook does will not allow the commit if the commit author and the person pushing the commit are not the same. However, there are plenty of use-cases in real development environment where a developer needs to push commits of other valid Bitbucket users (eg: locally merge changes from other developers workspace, and then push the branch to Bitbucket server, clone a repository from Bitbucket and push it back to a different remote url within Bitbucket server etc...)

I am request your development team to update the inbuilt pre-receive hook and allow all commits being pushed, as long as the author of the commits is a valid Bitbucket user.