Error When changing out of office to in office for an employee in K2

Hi

Error: "Could not load type 'System.DateTimeOffset' from assembly 'mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. "

Appears when creating an instance of  a process for an employee who was out of office ;  then became in office after that instance is created.

I recently updated the k2 to version 4.8210.2.450