Crash 'Unable to cast object of type 'System.__ComObject' to type 'ITfThreadMgr'.'

* .NET Core Version: 3.1
* Windows version: (`Windows 10 Pro 19043.1645`)
* Does the bug reproduce also in WPF for .NET Framework 4.8?: Unknow
* Is this bug related specifically to tooling in Visual Studio (e.g. XAML Designer, Code editing, etc...)? No.
* Security issues and bugs should be reported privately, learn more via our [responsible disclosure guidelines](https://github.com/dotnet/wpf/blob/main/README.md#reporting-security-issues-and-security-bugs).

**Problem description:**
Unknown cause.
1.We used WebView2 (1.3.153.51) in our project, We are using WebView2 when the crash happens. I'm not sure if it has anything to do with this.
2.Is it possible that the problem is caused by the Chinese input ?

**Actual behavior:**

App crash at Dispatcher.GetMessagePump()


It looks like the ‘threadManager’ value is of the wrong type?


**Expected behavior:**

**Minimal repro:**