Incorrect predicate in a left outer join query

table A
+------+
| a_id |
+------+
| 1    |
| 2    |
+------+
table B
+------+--------+
| b_id | amount |
+------+--------+
| 1    | 10     |
| 1    | 20     |
| 2    | NULL   |
+------+--------+
table C
+------+------+
| a_id | b_id |
+------+------+
| 1    | 1    |
| 2    | 2    |
+------+------+

select count(1) from (
    select t2.a_id,t2.amount1,t2.amount2
    from( select a_id from a) t1
    left outer join (
        select c.a_id,sum(amount) as amount1,sum(amount) as amount2
        from b join c  on b.b_id = c.b_id group by c.a_id) t2
    on t1.a_id = t2.a_id
) t;

select count(1) from (
    select t2.a_id,t2.amount1
    from( select a_id from a) t1
    left outer join (
        select c.a_id,sum(amount) as amount1,sum(amount) as amount2
        from b join c  on b.b_id = c.b_id group by c.a_id) t2
    on t1.a_id = t2.a_id
) t;

+-------------------------------------------------------------+
| Explain String                                              |
+-------------------------------------------------------------+
| Max Per-Host Resource Reservation: Memory=10.84MB Threads=8 |
| Per-Host Resource Estimates: Memory=143MB                   |
| Codegen disabled by planner                                 |
|                                                             |
| PLAN-ROOT SINK                                              |
| |                                                           |
| 12:AGGREGATE [FINALIZE]                                     |
| |  output: count:merge(*)                                   |
| |  row-size=8B cardinality=1                                |
| |                                                           |
| 11:EXCHANGE [UNPARTITIONED]                                 |
| |                                                           |
| 06:AGGREGATE                                                |
| |  output: count(*)                                         |
| |  row-size=8B cardinality=1                                |
| |                                                           |
| 05:HASH JOIN [RIGHT OUTER JOIN, PARTITIONED]                |
| |  hash predicates: c.a_id = a_id                           |
| |  other predicates: sum(amount) = sum(amount)      <---------- Wrong inferred predicate which incorrectly reject nulls
| |  runtime filters: RF000 <- a_id                           |
| |  row-size=16B cardinality=2                               |
| |                                                           |
| |--10:EXCHANGE [HASH(a_id)]                                 |
| |  |                                                        |
| |  00:SCAN HDFS [default.a]                                 |
| |     partitions=1/1 files=1 size=4B                        |
| |     row-size=4B cardinality=2                             |
| |                                                           |
| 09:AGGREGATE [FINALIZE]                                     |
| |  output: sum:merge(amount)                                |
| |  group by: c.a_id                                         |
| |  row-size=12B cardinality=2                               |
| |                                                           |
| 08:EXCHANGE [HASH(c.a_id)]                                  |
| |                                                           |
| 04:AGGREGATE [STREAMING]                                    |
| |  output: sum(amount)                                      |
| |  group by: c.a_id                                         |
| |  row-size=12B cardinality=2                               |
| |                                                           |
| 03:HASH JOIN [INNER JOIN, BROADCAST]                        |
| |  hash predicates: b.b_id = c.b_id                         |
| |  runtime filters: RF002 <- c.b_id                         |
| |  row-size=16B cardinality=3                               |
| |                                                           |
| |--07:EXCHANGE [BROADCAST]                                  |
| |  |                                                        |
| |  02:SCAN HDFS [default.c]                                 |
| |     partitions=1/1 files=1 size=8B                        |
| |     runtime filters: RF000 -> default.c.a_id              |
| |     row-size=8B cardinality=2                             |
| |                                                           |
| 01:SCAN HDFS [default.b]                                    |
|    partitions=1/1 files=1 size=15B                          |
|    runtime filters: RF002 -> b.b_id                         |
|    row-size=8B cardinality=3                                |
+-------------------------------------------------------------+