Master Version: older version a -->new version b
1. User create branch c from master a
2. User make some changes in branch c
3. User merge master b to branch c
4. User pull request to auto merge branch c to master
Expect differences in Bitbucket Diff page: Only user changes in step2
Actual differences in Bitbucket Diff page: Also changes made by others from a to b besides user changes in step2. This make the Diff Page a mess, not convenient to check real differences
