If the name of a report contains ampersand, then the export of the project display a warning. For example if the name of the report is "R&D", then you will get:

PHP Warning: SimpleXMLElement::addChild(): unterminated entity reference D in /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report.class.php on line 1713
PHP Stack trace:
PHP 1. {main}() /usr/share/tuleap/src/utils/export_project_xml.php:0
PHP 2. ProjectXMLExporter->export() /usr/share/tuleap/src/utils/export_project_xml.php:139
PHP 3. ProjectXMLExporter->exportPlugins() /usr/share/tuleap/src/common/Project/ProjectXMLExporter.class.php:160
PHP 4. EventManager->processEvent() /usr/share/tuleap/src/common/Project/ProjectXMLExporter.class.php:148
PHP 5. EventManager->dispatch() /usr/share/tuleap/src/common/Event/EventManager.class.php:98
PHP 6. EventManager->processEventOnListener() /usr/share/tuleap/src/common/Event/EventManager.class.php:146
PHP 7. Tuleap\Plugin\PluginLoader->Tuleap\Plugin\{closure:/usr/share/tuleap/src/common/plugin/PluginLoader.php:70-73}() /usr/share/tuleap/src/common/Event/EventManager.class.php:116
PHP 8. EventManager->eventManagerDispatch() /usr/share/tuleap/src/common/plugin/PluginLoader.php:72
PHP 9. trackerPlugin->exportXmlProject() /usr/share/tuleap/src/common/Event/EventManager.class.php:127
PHP 10. TrackerXmlExport->exportToXmlFull() /usr/share/tuleap/plugins/tracker/include/trackerPlugin.php:1352
PHP 11. TrackerXmlExport->exportTracker() /usr/share/tuleap/plugins/tracker/include/TrackerXmlExport.class.php:98
PHP 12. Tracker->exportToXML() /usr/share/tuleap/plugins/tracker/include/TrackerXmlExport.class.php:163
PHP 13. Tracker->exportTrackerToXML() /usr/share/tuleap/plugins/tracker/include/Tracker/Tracker.class.php:2235
PHP 14. Tracker_Report->exportToXml() /usr/share/tuleap/plugins/tracker/include/Tracker/Tracker.class.php:2337
PHP 15. SimpleXMLElement->addChild() /usr/share/tuleap/plugins/tracker/include/Tracker/Report/Tracker_Report.class.php:1713