We did resolve this issue. The phones do reboot sometimes, but that could be something else on the network. The main resolution that fixed this for us was VLANning. We were in on large broadcast domain. While we cant technically confirm this was the issue as I had network experts indicating that the phones should be able to handle this, they could not. We split the entire network up into 12 different vlans and have the phones in one of their own. The phones have not acted as before since 2013. They are stable. Let me know if you have any questions.