I've had issues for a while now with the Netflix app on the TiVo box (not V6, older one). It seems that almost every other time that I start streaming a film, the app freezes within 10-20 seconds. The TiVo box stops responding altogether - the buttons on the TiVo box and remove don't respond. The only thing I can do is restart the TiVo box. This is increasingly annoying as the whole boot-up sequence isn't exactly fast, especially if you then also have to wait for Netflix to reload, then find the film you were watching again; when this happens Netflix doesn't seem to add the file to your recently watched list.
This is not specific to my TiVo box, the same thing happened on my partner's TiVo too (this is the same version).