Unable to load netstandard2.1 assembly using powershell import-module

I have created a sample function app with the latest .netcoreapp3.1 and when I try to do import-module I am facing this below issue. I think System. Runtime DLL missing in netstandrad2.1.

Import-Module : Could not load file or assembly 'System.Runtime, Version=4.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The
system cannot find the file specified.

I have tried with the same function app creation using .netcoreapp2.2 and it is working. I am able to load the module. Please look into this issue.