Cannot assign more than one data acess policy to a user

When trying to assign a second data access policy to a user, I get an error saying:

> An invalid access policy assignment was detected due to duplicate entries. Please review and ensure that each assignment has a unique combination of assignmentName, policyName and ObjectId to avoid such duplicates

I have tried using both portal and az cli and I get the same error. I have tried different combinations of users, policies and assignment names (when using az cli) and all result in the same. So I think either there is a bug preventing me from assignment multiple data access policies to a user or the error and documentation is misleading.

按照描述，分别使用 Azure portal 和 az CLI 复现分配，并改变用户、策略和分配名称。确定用户是否可以接收多个 data access policies，以及重复条目错误或其文档是否不正确；当行为和预期的分配格式得到明确时，即视为完成。

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