I used to do git amend in the following simple way git commit --amend. Recently I started using message from file option (-F), like so: git commit --amend -F my_git_message.txt.
My workflow includes git-review tool which I call after each commit: git review --reviewers user1 user2.
After I started using -F option when amending, seems like git-review started creating a new review, instead of amending the change to an old review. Why is this happening?