Missing group by in NodeRevisionDelete->getCandidatesRevisions()

We have the following error with MySQL 5.6, while MySQL 5.7 has no problems with the SQL statement.
Drupal\Core\Database\DatabaseExceptionWrapper: SQLSTATE[42000]: Syntax error or access violation: 1055 'database.r.revision_timestamp' isn't in GROUP BY: SELECT t.vid AS vid FROM (SELECT r.vid AS vid, r.revision_timestamp AS revision_timestamp FROM {node_field_data} n INNER JOIN {node_revision} r ON r.nid = n.nid WHERE (type = :db_condition_placeholder_1) AND (n.nid = :db_condition_placeholder_2) AND (changed < :db_condition_placeholder_3) AND ((n.vid <> r.vid)) GROUP BY n.nid, r.vid ORDER BY revision_timestamp DESC LIMIT 9223372036854775807 OFFSET 0) t WHERE revision_timestamp < :db_condition_placeholder_0; Array ( [:db_condition_placeholder_0] => 1568794622 [:db_condition_placeholder_1] => artikel [:db_condition_placeholder_2] => 47391 [:db_condition_placeholder_3] => 1566116222 ) in Drupal\node_revision_delete\NodeRevisionDelete->getCandidatesRevisions() (line 331 of docroot/modules/contrib/node_revision_delete/src/NodeRevisionDelete.php).

The inner query has a missing group by statement:

SELECT r.vid AS vid, r.revision_timestamp AS revision_timestamp
FROM {node_field_data} n
INNER JOIN {node_revision} r ON r.nid = n.nid
WHERE (type = :db_condition_placeholder_1) AND (n.nid = :db_condition_placeholder_2) AND (changed < :db_condition_placeholder_3) AND ((n.vid <> r.vid))
GROUP BY n.nid, r.vid
ORDER BY revision_timestamp DESC
LIMIT 9223372036854775807 OFFSET 0

The select is on vid and revisions so the group by should be on those fields as well.