CommitDate timestamp is one hour off

Summary

Rebase a branch will fill in wrong timestamp to the commitDate

Steps to reproduce

Rebase an outdated branch by clicking on the button and then merge.

What is the current bug behavior?

The timezone isn't correct. If you check the timestamps, the commitDate is older than the AuthorDate. When you don't format the date, you can see the full date in UTC is correct. If output the timestamp (UTC), it's a hour off.

What is the expected correct behavior?

Correct timestamp

Output of checks

This bug happens on GitLab.com