diff --git a/app/models.py b/app/models.py
index c3ef0c0..ce94029 100644
--- a/app/models.py
+++ b/app/models.py
@@ -172,7 +172,7 @@ class Alarm(db.Model):
     bridge = db.relationship("Bridge", back_populates="alarms")
 
     def update_state(self, state: AlarmState, text: str):
-        if self.alarm_state != state:
+        if self.alarm_state != state or self.state_changed is None:
             self.state_changed = datetime.utcnow()
         self.alarm_state = state
         self.text = text