Plantronics + Polycom.
Now together as
To update this thread, since removing the BLF entries and making no other configuration changes the system has been rock-solid for 3 weeks. Adding a BLF entry to a handset will crash it within two days.
Our reseller says they have submitted a ticket.
I can't remember if you ever mentioned or not whether you are using Asterisk, but while we wait for a fix from Polycom, I have developed a patch for Asterisk that should largely prevent this situation from occurring when using BLFs. I posted the patch in my thread about this topic: http://community.polycom.com/t5/VoIP/SoundPoint-IP-650-lockups/m-p/52336#M8392