All of a sudden I am logged in as another user in my domain

> Please provide us with the following information:
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### This issue is for a: (mark with an `x`)
```
- [x ] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
> I was logged in as my userid@myofficedomain.com and was logged in as is for many months - today when I hit the the URL, I was logged in as another user in my officedomain. This happened to 2-3 other people in the past one year. Is somehow the session_key get mixed up in the django-session table ? This ideally shouldn't be possible but it has happened.

### Any log messages given by the failure
>

### Expected/desired behavior
> logged in users should be logged in as themselves only

### OS and Version?
> Ubuntu
### Versions
> 20.04

### Mention any other details that might be useful

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> Thanks! We'll be in touch soon.

首先检查 Django 的会话处理和 django-session 表，因为报告怀疑会话密钥在用户之间发生了混用。如果可能，复现登录流程，并检查会话如何与用户关联；当用户始终保持以自己的身份登录，且跨用户行为由验证测试覆盖时，即视为完成。

由索引模型根据 Issue 内容生成。