redmine says, content was changed by another user but it's not true.

Added by Michael Aye over 11 years ago

while working on issue 31 on our redmine system, another user updated issue 33, as visible by email notification.
Immediately after that i tried to save my changes to 31 but redmine stated that another user changed the content of the issue.
I removed my changes and checked to see if something else was changed with issue 31, but it wasn't.
Unless this was not just coincidal, I wonder why redmine gave me that error message?

My system:
redmine 0.8-stable, revision 2337
ruby 1.8.6
Rails 2.1.2