Our FortiFone-480 desk phones are randomly experiencing ring delays after upgrading the firmware to 126.96.36.199. When there is an incoming call, some of the 480 phones will not ring for about 15 seconds. Not only is the phone not ringing but the SIP packets do not appear to be reaching the phone as it doesn't even show the line is in use. So far I have been unable to replicate the issue on demand but I am taking a long term net cap for one phone to see if I can see anything from that after this issue occurs again. Has anyone else experienced this?
Some further information to pass along. We are using LLDP to configure the VLAN, and priority values.
Some additional observations; When a call comes in from an outside line it rings a call group, the call group rings all included extensions. When this issue occurs, the phones that are ringing show via the soft keys, that some phones are ringing and some phones are not ringing by way of a flashing green light and a solid green light respectively. On a phone that isn't ringing, the line will be picked up by another extension then a few seconds later it will have a very brief ring even though the call has been answered already. I accidently deleted my pcap I had showing the issue from the FVE100 perspective so I will try to get that again.
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