use sharding-jdbc，sharding DB，seata cannot roll back。

Ⅰ. Issue Description
Using sharding-jdbc，if just sharding table seata ATmode can roll back，seata ATmode cannot roll back when use sharding DB，anyone kown why？
使用sharding-jdbc整合seata AT模式，A业务调用B业务和C业务，如果C业务异常，手动回滚全局事务。在A,B,C单库分表场景下seata可以正常回滚，在分库场景下不稳定，经常出现A业务回滚，B业务不会滚的情况，有人知道原因吗？

### II. Environment:

-sharding-jdbc version：4.1.0
-seata version:1.3
-springboot:2.2.9.RELEASE

Start by reproducing the A/B/C global transaction with sharding-jdbc 4.1.0, Seata 1.3, and Spring Boot 2.2.9.RELEASE, comparing sharded-table and sharded-database setups. Capture the rollback behavior and transaction details for each service; done means the cause of the inconsistent rollback is identified and a verified fix or limitation is documented.

Written by the indexing model from the issue text.