Yale Connexis L1 unlocked itself, but why, IDE Logs


So Yale Connexis L1 has unlocked itself several times over the last few days when it should have. I locked the door as I left and exactly 3hrs later the lock unlocks. ST was still in away mode, door never open (which should trigger a relock autamatically after 3mins) So looking in the IDE logs I can see the offending entry:

Name 	Value
archivable 	true

    "lockName": "Front Door Lock"

date 	2018-05-10 12:41:54.777 PM BST (2018-05-10T11:41:54.777Z)
description 	Unlocked
deviceId 	5778cca1-fc16-4a08-a5ef-b87ec95eddce
deviceTypeId 	8a2a823b3c988884013c98891a8a0003
displayed 	true
eventSource 	DEVICE
groupId 	6bdd37c7-04bc-48ba-a1ed-95ed1a6dc006
hubId 	f0d8137c-9741-40ab-88e2-1b37fa5ed67a
id 	2360fe3e-5447-11e8-9d5b-bd5f3cd0da6e
isStateChange 	true
isVirtualHub 	false
linkText 	Front Door Lock
locationId 	e407e542-19d3-4f44-b285-c912385965d8
name 	lock
translatable 	false
unixTime 	1525952514777
value 	unlocked
viewed 	false

how can I find out what trigged this?

Just to add, the only time this lock should unlock itself is when ST detects presence with the presence sensor, it activates “Home” automation which amongst other things unlocks the door. There is only one of the sensors, and it was 100miles away when the door unlocked.

this indicates that the lock was unlocked physically from the device itself. (the source was the device)