pt-archiver a table with json type column to a file, encoding error

hello
1. table contents as following:±—±-----------------+| id | tt               |±—±-----------------+| 14 | {“ss”: “哈哈”}   |
2. result of  pt-archiver   and  --file option:   14      {“ss”: “哈哈”}
3. table structure:CREATE TABLE tt1id int(10) unsigned NOT NULL AUTO_INCREMENT,  tt json DEFAULT NULL,  PRIMARY KEY (id)) ENGINE=InnoDB AUTO_INCREMENT=16 DEFAULT CHARSET=utf8
4.  pt-archiver  dsn   charset:utf85. MySQL characterset| character_set_client     | utf8                       || character_set_connection | utf8                       || character_set_results    | utf8                       || character_set_server     | utf8mb4                    |

when  no json type column, everything works well, contents in archived file are correct. so ,I thought that  errors occurred when writing  from resultset to dest file.

It looks like you’ve opened a bug report and I have confirmed it: https://jira.percona.com/browse/PT-1875. I do not have a workaround for now though.