1. In Hue, take menu choice
Query Editors -> Impala
2. Enter the query
select round(117/7, 2);
3. Click Execute
You see result 16.710000000000001
You should see result 16.71
I get a similar presentation error with Hive on Hue, and with different rounding arguments.
Hive and Impala work as expected when using their shells directly rather than Hue.