Compilation error on customer system but not locally

Hi all,

I'm having the strangest compiler error on a customer system, while the exact same object compiles on my local system, using the same NAV build (2016 CU12).


The variables:
String DotNet System.String.'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'
CultureInfo DotNet System.Globalization.CultureInfo.'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Any ideas why this could happen? It must be environment right?

Gr, Erik