Not getting the difference changes on comparing two git branches in same repo using Github API

I am able to get difference between two branches stage and master under same repo on web version via below web URL.

https://github.com/:username/:repo/compare/master…staging

but not getting the changes via Github API:

https://docs.github.com/en/rest/commits/commits?apiVersion=2022-11-28#compare-two-commits

below snapshot display output of above compare API, here it shows list of all commits but it missed the key patches for filename composer.lock that supposed to be have all file changes.