Materialized view query rewrite fails if query has decimal derived aggregate

create table t1 (a int, b decimal(3,2)) stored as orc TBLPROPERTIES ('transactional'='true');

create materialized view mv1 as
select a, sum(b), count(b) from t1 group by a;

explain cbo
select a, avg(b) from t1 group by a;

CBO PLAN:
HiveProject(a=[$0], _o__c1=[CAST(/($1, $2)):DECIMAL(7, 6)])
  HiveAggregate(group=[{0}], agg#0=[sum($1)], agg#1=[count($1)])
    HiveTableScan(table=[[default, t1]], table:alias=[t1])