I am not able to reproduce this problem. The stack trace does not seem to contain any relevant information. Are you absolutely sure that the only change is as indicated?

To try to reproduce the problem, I have created a logic class with the following:

@Action(verbs = Verbs.UPDATE)
public void setPercentWorkerWorkpackageUpdatingNumEstimatedHoursMonth() throws Exception{
    System.out.println("ACTION: setPercentWorkerWorkpackageUpdatingNumEstimatedHoursMonth");
}

I then wrote a simple test program that updates an object, and the action got called as expected, without any exception.

Would you have a more complete stack trace, and/or log, so we could try to locate the problem more precisely?