I just ran into a 112 alarm last week. Never saw one before, needed to look it up.
There was a network issue involving several carriers, apparently caused by a truck hitting a pole outside the Central Office. The end result was the phone system getting slammed with errors on both the SIP trunks and the voice VLAN, which are provided by different carriers.
Alarm 112 popped up, and came back after being cleared twice. Call volume was very low at the time. We checked with Mitel, they thought it was probably due to all the network errors. They suggested rebooting the system, which I did after hours.
I was concerned that the system would reboot on its own, but it didn't. It's been good for eight days now.