I can't reproduct my issue, this is my first time, but my colleague came across this issue several weeks ago.
After I pushed my commit to git server without rejection. I run git pull --rebase, then I got a forced update, and my last commit is missing.
I have asked a question on StackOverflow, there is more details about this issue: https://stackoverflow.com/questions/49164906/why-git-pull-rebase-results-a-forced-update
I have no idea about this.
I'm using Ubuntu 16.04.4 with Git 2.16.2, PyCharm IDE.
---- Sincerely, Tian Zhen