Spotted on Enalean's server while doing the validation of Tuleap 12.6
PHP Notice: Trying to access array offset on value of type bool in /usr/share/tuleap/plugins/statistics/include/DiskUsage/ConcurrentVersionsSystem/Retriever.php on line 43
and
PHP Notice: Trying to access array offset on value of type bool in /usr/share/tuleap/plugins/statistics/include/DiskUsage/Subversion/Retriever.php on line 43