not possible to clone tasks with special characters like german umlaut (encoding problem)

if I have tasks with german umlaut in field description and I read this task with az cli, I got wrong encoded characters. If I try to use these characters to create a new task, the content of the new task is also wrong

**Steps to reproduce**
1. create a work item in azure devops and add in the description field the following content "öäü"
2. save the work item and remember the id the new work item got
3. use az cli to read the work item
`$xx=(az boards work-item show --id --org )`
4. convert the json output into powershell object with `$xx=$xx | ConvertFrom-Json`
5. look into the field `$xx.fields.'System.Description'`
6. you should now got the following: `

`

**Expected behavior**
`

`

**Environment summary**
Windows 10 client
az--version:
azure-cli 2.19.1
core 2.19.1
telemetry 1.0.6
Extensions:
azure-devops 0.18.0
Python location 'C:\Program Files (x86)\Microsoft SDKs\Azure\CLI2\python.exe'
Extensions directory 'C:\Users\pern\.azure\cliextensions'
Python (Windows) 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 23 2018, 23:31:17) [MSC v.1916 32 bit (Intel)]
Legal docs and information: aka.ms/AzureCliLegal
Your CLI is up-to-date.

Powershell version: 5.1.18362.1171

**Additional context**
if you run the command with `--debug`, you see that there is an encoding like `

`, but it's not possible to change