This was all discussed back in May and Jim blamed it on a Help file timer that he then changed to only run when the Help file was the active window. I tried to show that the problem existed when the Help file was open but not the active window - just as you are indicating. He also said he doubted it was actually using that much of the CPU’s resources but that the Activity monitor only thought it was.
Just as a precaution I have gotten into the habit of closing the Help file when not directly using it. I have also had occasion when using this file where the search box will no longer respond to typing and I have to close the window and reopen a new copy to continue.