RunAs not working with Passwordstate credentials

RDM v2020.3.24.0

I'm trying to create a simple cmd.exe session that will run as a different user. I'm specifying credentials in my linked Passwordstate credential entry. When I execute the session, I get a "Unable to execute the application "c:\windows\system32\cmd.exe". When I change the RunAs credentials to Custom, and enter the same username/password from the Passwordstate entry, it works as expected. I can use the same linked Passwordstate credentials in an RDP session successfully, so I know they're valid. I can also manually run cmd.exe and execute runas from there with the same credentials and they work. As another test, I defined an After Open action to pop up a message box and display the %USERNAME%, %PASSWORD%, and %DOMAIN% variables. I made sure to enable "Use Password in Variables" too. When the message box comes up, it shows "%DOMAIN% ngagne %PASSWORD%" - the domain and password variables don't resolve.

I get the following in the RDM application log when it fails:

1/14/2021 12:18:09 PM2020.3.24.0 - 64-bitError SilentSystem.ComponentModel.Win32Exception (0x80004005): The stub received bad data
  at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
  at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
  at Devolutions.RemoteDesktopManager.Frames.Embedded.FreEmbeddedCmd.StartProcess(EmbededConnectionResult embededConnectionResult)
  at Devolutions.RemoteDesktopManager.Frames.Embedded.FreEmbeddedCmd.ProcessVisibleChanged()