After upgrading from Hive1 to Hive3, Decimal computation experiences a loss of precision

I can reproduce this bug.

create table decimal_test(
    id int,
    quantity decimal(38,8),
    cost decimal(38,8)
) stored as textfile;
 
insert into decimal_test values(1,0.00008000, 0.00015000);
 
select quantity * cost from decimal_test;

1、The following are the execution results and execution plan on Hive-1.0.1：

2、The following are the execution results and execution plan on Hive-3.1.3：