The problem seen is, when a PC is connected to the access port of the phone, when there is either broadcast or Multicast traffic it looks like the port just shuts down. We have mainly seen it happen when the PC is a Apple of some sort but we have also seen it when a PC is attached as well.
An example is DHCP. We have seen this with a notebook that when attached to the phone, will not get a DHCP IP addres. Remove the phone and the PC works fine, the Phone works fine at all times. The first time this was picked up was when the customer was trying to re-image a PC using Alteris, when attached to a phone the build would fail when the phone was removed the build would work correctly.
Upgraded the firmware to version: SCCP41.8-4-1SR2S, but still seeing the same problems.
There are about approx 80 x 7941's in production.