Hi shackbill, it sounds like your best bet right now is to update Asterisk to a later version. You should be able to achieve this with the “asterisk-version-switch”, and then “fwconsole restart”. Staying on 13 should be fine, but I’m being told about an MWI Notification issue that was resolved in versions 13.29.2 and later, which could possibly cause issues like yours.
If the problem persists after the update, there are a couple paths to take next. You’ll want to get a packet capture of the sip traffic to the phone as the problem happens. Maybe once it’s noticed on one of the phones, the customer can contact you, and you can make a capture while having you or someone place a call to that phone, before rebooting it.
If these phones are within warranty, contact Support to have a ticket created and they can start troubleshooting. The packet capture will help them as well.
