Netgear LLDP implementation dropping VLAN tags

[Lightfoot101]

Hi All,

Having a strange issue here with our newly installed phone system.  

We have implemented autovoip / LLDP and are daisy chaining our pc's and laptops of the back of our phones (ploycom vvx 450's)

phones are sucessfully being added to the voice VLAN (VLAN2) on boot and PC's always end up on their own VLAN (VLAN3) as i expect.

We have noticed that after a period of time, phones are dropping off the network and on their display are presenting a "no network available" message.  When this happens, we can see that the switchport the phone is connected to has reset back to being untagged for the voice VLAN (VLAN2).  Tagging the port again for the voice VLAN instantly brings the phone online again, but i have yet to find a configuration where the tagged status for the voice VLAN on any given port will remain static.

this issue can happen randomly throughout the day, but we can predict it happening usually around 10 -20 minutes after a user has turned off or disconnected their PC or laptop from the phone.

Any help would be appreciated.

So far I tried moving switchports from Hybrid to trunk without sucess.

Original port config - Blow

switchport hybrid pvid 3
switchport hybrid allowed vlan add 2 tagged
switchport hybrid allowed vlan add 3 untagged
switchport hybrid allowed vlan remove 1

[Lightfoot101]

I've also disabled AutoVOIP for all ports and it looks like phones are still correctly being added to the correct VLAN when booting, so im guessing these setting are picked up via the Voice VLAN settings as opposed to AutoVOIP.  

The issue still seems to be ongoing however - I've also tried switching specific ports between Hybrid and Trunk mode to see if that would make the VLAN tag more persistant but it still seems to dropping off some ports particularly when the attached pc or laptop is disconnected, shutdown, goes to sleep or wakes up