diff --git a/core/adaptive_meds.py b/core/adaptive_meds.py
index 44b9e06..0de4e2f 100644
--- a/core/adaptive_meds.py
+++ b/core/adaptive_meds.py
@@ -67,7 +67,8 @@ def record_presence_event(user_uuid: str, event_type: str, timestamp: datetime):
     if not presence:
         return
 
-    history = json.loads(presence.get("presence_history", "[]"))
+    raw_history = presence.get("presence_history", [])
+    history = json.loads(raw_history) if isinstance(raw_history, str) else raw_history
 
     # Add new event
     history.append({"type": event_type, "timestamp": timestamp.isoformat()})
@@ -88,7 +89,8 @@ def calculate_typical_wake_time(user_uuid: str) -> Optional[time]:
     if not presence:
         return None
 
-    history = json.loads(presence.get("presence_history", "[]"))
+    raw_history = presence.get("presence_history", [])
+    history = json.loads(raw_history) if isinstance(raw_history, str) else raw_history
     if len(history) < 3:
         return None