Columnstore provided udf median()/avg_mode() not working

Enabled median udf provided on article:
https://mariadb.com/kb/en/library/columnstore-user-defined-aggregate-and-window-functions/

But mostly 90% of the time that error appears when calling a query with median:

Error Code: 1815. Internal error: prep2PhasesAggregate: A UDAF function is called but there's no UDAFColumn

Query is kinda simple:

SELECT v1, median(v2) as a FROM testtable
group by v1;