I just got of the phone with Logitech, after troubleshooting for my Harmony 890. My 890 was locking up. Long story short, there seems to be a problem in there firmware that if you change the name of a activity, that may cause your remote to freeze up. The folks at Logitech will have to rename your device so your remote will not lock up.
Logitech said they are working on this problem.