Diff is not run on the correct objects and leads to a fatal error

2018-08-21T14:35:41+02:00 [8464] [error] Unhandled exception: Command execution failure: /opt/rh/rh-git29/root/usr/bin/git --work-tree='/var/lib/codendi/gitolite/repositories/new-websites/tuleap.org.git' --git-dir='/var/lib/codendi/gitolite/repositories/new-websites/tuleap.org.git' diff --no-renames --numstat 'ee4399550237833648f70017df0c2d23f283f247'...'39ae460f4231d901539106b82980fe4380a99675' -- '*' (return value: 128):
fatal: Invalid symmetric difference expression ee4399550237833648f70017df0c2d23f283f247:
#0 /usr/share/tuleap/plugins/git/include/Git_Exec.class.php(338): Git_Exec->execInPath('diff --no-renam...', Array)
#1 /usr/share/tuleap/plugins/pullrequest/include/PullRequest/GitExec.php(159): Git_Exec->gitCmdWithOutput('diff --no-renam...', Array)
#2 /usr/share/tuleap/plugins/pullrequest/include/PullRequest/GitExec.php(148): Tuleap\PullRequest\GitExec->getFileDiffStat('ee4399550237833...', '39ae460f4231d90...', '*')
#3 /usr/share/tuleap/plugins/pullrequest/include/PullRequest/REST/v1/PullRequestRepresentationFactory.php(72): Tuleap\PullRequest\GitExec->getShortStat('ee4399550237833...', '39ae460f4231d90...')
#4 /usr/share/tuleap/plugins/pullrequest/include/PullRequest/REST/v1/PullRequestsResource.php(294): Tuleap\PullRequest\REST\v1\PullRequestRepresentationFactory->getPullRequestRepresentation(Object(Tuleap\PullRequest\PullRequestWithGitReference), Object(GitRepository), Object(GitRepository), Object(Tuleap\PullRequest\GitExec), Object(PFUser))
#5 [internal function]: Tuleap\PullRequest\REST\v1\PullRequestsResource->get(279)
#6 /usr/share/tuleap/src/vendor/luracast/restler/vendor/Luracast/Restler/Restler.php(1059): ReflectionMethod->invokeArgs(Object(Tuleap\PullRequest\REST\v1\PullRequestsResource), Array)
#7 /usr/share/tuleap/src/vendor/luracast/restler/vendor/Luracast/Restler/Restler.php(304): Luracast\Restler\Restler->call()
#8 /usr/share/tuleap/src/www/api/index.php(117): Luracast\Restler\Restler->handle()
#9 {main}