Executing a step similar to the following fails:

steps
{
  bat returnStatus: true, script: '''
  SET PATH = %PATH%;"C:ʅʅsomeʅʅpath"
  PATH'''
}

(I had to use special characters above because double back-slashes aren't displayed correctly by Jira.)

 The path is not being set:

[Pipeline] bat
[Jenkins Test-Pipeline] Running batch script

C:\Program Files (x86)\Jenkins\workspace\Jenkins Test-Pipeline>SET PATH = C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files\Docker\Docker\Resources\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files\nodejs\;C:\Program Files\Git\cmd;C:\Windows\system32\config\systemprofile\AppData\Local\Microsoft\WindowsApps;"C:\some\path"

C:\Program Files (x86)\Jenkins\workspace\Jenkins Test-Pipeline>PATH
PATH=C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files\Docker\Docker\Resources\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\Program Files\nodejs\;C:\Program Files\Git\cmd;C:\Windows\system32\config\systemprofile\AppData\Local\Microsoft\WindowsApps