2.1.2版本历史数据迁移问题（旧表为JSON字段类型，新表为Variant字段类型）

方便提供一下复现的sql、相应的表结构和部分数据吗

create table t1(
target_index varchar(1024),
primarykey varchar(1024),
content_version varchar(1024),
content JSON,
time datetime default current_timestamp
)DUPLICATE KEY(target_index,primarykey,content_version)
DISTRIBUTED by hash(target_index) buckets 10
properties(
"replication_allocation" = "tag.location.default:1",
"min_load_replica_num" = "-1",
"is_being_synced" = "false",
"storage_medium" = "hdd",
"storage_format" = "V2",
"inverted_index_storage_format" = "V1",
"light_scheme_change" = "true",
"storage_row_column" = "true",
"disable_auto_compaction" = "false",
"enable_single_replica_compaction" = "false",
"group_commit_interval_ms" = "1000",
"group_commit_data_bytes" = "134217728"
);

create table t2(
target_index varchar(1024),
primarykey varchar(1024),
content_version varchar(1024),
content Variant,
time datetime default current_timestamp
)UNQIUE KEY(target_index,primarykey,content_version)
DISTRIBUTED by hash(target_index) buckets 10
properties(
"replication_allocation" = "tag.location.default:1",
"min_load_replica_num" = "-1",
"is_being_synced" = "false",
"storage_medium" = "hdd",
"storage_format" = "V2",
"inverted_index_storage_format" = "V1",
"enable_unique_key_merge_on_write" = "true",
"light_scheme_change" = "true",
"storage_row_column" = "true",
"disable_auto_compaction" = "false",
"enable_single_replica_compaction" = "false",
"group_commit_interval_ms" = "1000",
"group_commit_data_bytes" = "134217728"
)

insert into t2
select
target_index,
primarykey,
content_version,
content
from t1;

content数据类似如下：
{
"name": "test",
"age": "18",
"picture": [
{
"bz": "test",
"id": "1",
"url": "http://asdasdas/asda/asd.jpg"
},
{
"bz": "test2",
"id": "2",
"url": "http://asdasdas/asda/asd1.jpg"
}
]
}
里面除了picture是确定的，其他字段都是不确定的。

尝试升级到2.1.5，如果还有问题，可以贴一下be.out的栈