Bad render of Bar Chart .

Below I present simplified scenario of my production case which is a bit more complicated . It has been done using APEX 21 Patch set 8 (freshly installed)

The idea is to show appearance of top 3 ITEMs day-by-day. It has been achieved by query like below:

 select kpdate, kpitem, kpcount, kprank

  from uniqa_admin.kp_chart

 where kprank <=3

 union

 select kpdate, 'others', sum(kpcount), 999

  from uniqa_admin.kp_chart

 where kprank >3

 group by kpdate

 order by 1,4

Result in sqlplus/toad/sqldeveloper is :

It is exactly what I expect, data are sorted first by date and then by the last column KPRANK. This allows to sort column KPCOUNT first by the TOP 3 letters and then sum all others on the fourt position. What could be important (for APEX) every day different letters could appear in top three.