Commit timestamps differ in commits tab of MRs

The commits "c" and "d" in this MR https://gitlab.com/zimmskal/test/merge_requests/1/commits have different timestamps in the tool tip than in their commit detail view https://gitlab.com/zimmskal/test/commit/83dd43c7c410c11f99cce09c77b8483542960e58 https://gitlab.com/zimmskal/test/commit/972bdfa44fb0a0a83b8bc9437ce821993ca086d0

I noticed this problem with our local instance of GitLab running 8.2.1 where in one MR the commits are differently sorted than they should be. However, I can only reproduce the differing timestamps not the differing ordering.

This is perhaps related to rebasing to commits, since we are doing that a lot before merging MRs.