We have written some tests that shows that this should be a problem, and that the git merge may have failed because of some other merge problem.
That merge problem isn't really reported in a good way, and the error reporting from the plugin hides the real cause of merge problems in some cases. Thus we have created
JENKINS-27690 to improve logging.
This issues will then be resolved, by now including tests that integrate commits with double quotes in one of the commit messages.