The plugin is adding a "?" char to all AssemblyInfo.cs files,
Ex.
?using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

// General Information about an assembly is controlled through the following
// set of attributes. Change these attribute values to modify the information

It do change the assembyVersion line correctly
[assembly: AssemblyVersion("4.6.7.1")]

But the build is failing because the ? at the beginning of the file