Window Functions don't work with arithmetic operators or other functions

Discovered during QA:

create table tb1 (d1 decimal(7,2), i1 int)engine=columnstore;
insert into tb1 values (7.12, 1), (12.12, 1);

select (sum(d1)*100.0) div sum(sum(d1)) over (partition by i1) from tb1 group by i1;

This results in a random output in 1.2, and a 0 output in 1.1. The answer is 100 as can be seen when using innodb:
MariaDB [dhall]> select (sum(d1)*100.0) div sum(sum(d1)) over (partition by i1) from inno_tb1 group by i1;
---------------------------------------------------------

---------------------------------------------------------

---------------------------------------------------------
1 row in set (0.008 sec)

Using the divide operator '/' instead of the div function may result in a different set of random numbers.