Steps to reproduce

Invoke-RestMethod -Uri $URI -Method Put -ContentType 'application/json' -Body '{"jsonrpc":"2.0","method":"get.object","params":{"latname":"testing","cyrname":"проверка"}}'

Expected behavior

http request json

{"jsonrpc":"2.0","method":"get.object","params":{"latname":"testing","cyrname":"проверка"}}

Actual behavior

http request json

{"jsonrpc":"2.0","method":"get.object","params":{"latname":"testing","cyrname":"????????"}}

Environment data

Name Value

PSVersion 6.1.0-rc.1
PSEdition Core
GitCommitId 6.1.0-rc.1
OS Microsoft Windows 10.0.17134
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0

Description

It works good if -InFile Parameter is used

Invoke-RestMethod -Uri $URI -Method Put -ContentType 'application/json' -InFile $FilePath 

File must be encoded in UTF-8 with no BOM

I think cmdlet encodes body to ASCII
In PS 5.1, 6.0 the same bug is.
Thanks