Hi, I have a new Harmony 890 that I am having trouble setting up. After setting up my devices and activities, the results were less than satisfactory. For example, it will turn on my tv but not my cable box. I followed the help screens and it fixed the problem. But, the next time I use it, the remote still won't turn on/off the box. I solved it again with help but the changes don't seem to stick. Why won't the remote learn its own fixes?