I'm using 2.0.18 ok, but nuget advised me that there was an update, so I decided to try it.

I run the repack in a post-build CMD file, with this snippet:
SET ILMERGE_VERSION=2.0.27
SET ILMERGE_PATH=%USERPROFILE%.nuget\packages\ilrepack%ILMERGE_VERSION%\tools\

Without doing anything else besides changing the minor version from 18 to 27, I get this error:

Failed to resolve assembly: 'Microsoft.VisualBasic.Core, Version=0.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'