EXP39 buttons fail to change status, phone requires reboot to fix

[Benoiti]

Hello, I have an ongoing issue with two remote extensions (T28P) with EXP39 consoles.

System: FreePBX Stable-3.211.63-10 64Bit running on Intel DN2800MT, 2gb ram with 64gb SSD

Yealink T28P firmware: 2.70.0.140
Hardware version: 1.0.0.39

EXP39 firmware: 5.16.0.0
Hardware version: 32.0.0.0

There are eight phone/console extensions on the local network and two phone/console extensions in another city which connect over the internet.

At least once a day, either of the two phones will receive notification packets of incoming calls and the console BLF LEDs will flash to indicate which extensions are ringing. When the call is answered, one of the LED's will continue to flash and the status icon on the LCD will still show the station as ringing. In this condition, the extension cannot be dialed by pressing the BLF button.

It us usually the extension that picked up the call. Sometimes, the extension will appear busy even though the call has ended. This only happens on the two remote extensions, never any of the local phones. I suspect this is partly caused by packet loss since we have a poor carrier system here and I have configured TCP on all extensions, as UDP is too unreliable over the public internet.

I tried calling the extensions in the hope that Asterisk would send out new status notifications to the extensions and cause the buttons to reset, but nothing seems to work and rebooting the phones is the only way to reset the LED's and the LCD display.