[Maria-developers] Different results from UNION and UNION DISTINCT

According to this post at Stack Overflow, MariaDB 10.1.10 gives wrong results (duplicate rows) for UNION DISTINCT while the UNION version gives correct ones. (notice the comment: http://dba.stackexchange.com/questions/141799/select-distinct-values-of-two-... ) The query in question is very simple: SELECT a AS result FROM tableXUNION DISTINCTSELECT b FROM tableX ; I couldn't find a related bug in the MDEV. Is this a known (or fixed) issue or should I go and add a bug report/ Pantelis Theodosiou