After pushing to bitbucket my collegues commits are deleted and a message appears on bitbucket newsfeed
stripped 6f9de58aa748 from projektA
4 hours ago
stripped
We also faced this recently. Quite annoying, I must say. But in our case, the stripped commits were restored immediately after the original user pushed again. The other thing that we did to avoid this from happening again was to disable "History Re-writes" on the branch in question.
Hope this helps someone who faces this in future!