This happened to me too this morning!!! The Siren went off and my lights entered ‘Brothel’ mode, although in the ST app SHM was showing Disarmed and no push notifications were sent saying the alarm went off - all very strange.
And again this evening… looks like the system is being set to Arm stay, being disarmed in the cloud but the local instance of SHM on the hub isn’t synced causing the siren to go and the lights to go red. What have Samsung fiddled around with this time…