I think this is a core api syntax error, if not, please route adequately:
ApiQueryContributions::execute 10.64.48.173 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'YY.YY.YY.90) ORDER BY rev_user_text LIMIT 501' at line 1 (10.64.48.173) SELECT DISTINCT NULL AS `actor_id`,rev_user AS `user_id`,rev_user_text AS `user_name` FROM `revision` WHERE (rev_user_text LIKE 'XX.XX.X%' ESCAPE '`' ) AND (rev_user_text YY.YY.YY.90) ORDER BY rev_user_text LIMIT 501
The errors are not that many, but this seems to me like a serious one with an easy fix:
https://logstash.wikimedia.org/goto/866e7cb237c59480b06b906c678949cf