What is the proper condition to check for a select list value of none?
Make sure to add a Rules condition Entity has field (related to your field field-client as shown in your first Rules Condition). For a video tutorial that illustrates the importance of this Entity has field condition, refer to Data types and data selection, especially what is shown between about 13:30 and 17:30 in it.

If that doesn't help, you may want to do some Rules debugging, as explained in the answer to "How can I display the value of a variable inside a condition?".