diff --git a/src/aare/daq/tellupdater.py b/src/aare/daq/tellupdater.py
index aaa39897..22da69be 100644
--- a/src/aare/daq/tellupdater.py
+++ b/src/aare/daq/tellupdater.py
@@ -263,20 +263,26 @@ def listen_to_sse():
         logger.info(f"[SSE] Reconnecting in {SSE_RECONNECT_DELAY_S} seconds")
         time.sleep(SSE_RECONNECT_DELAY_S)
 
-def compare_and_report_change(old, new, key_func):
-    """
-    Compare two lists of pucks and return (joined, left).
-    Ignore reference-tools puck(s) with tell_position 'X1'.
-    """
-    # Filter out reference-tools
-    old_filtered = [p for p in old if getattr(p, "tell_position", None) != "X1"]
-    new_filtered = [p for p in new if getattr(p, "tell_position", None) != "X1"]
 
-    old_ids = set(key_func(p) for p in old_filtered)
-    new_ids = set(key_func(p) for p in new_filtered)
+def compare_and_report_change(old, new):
+    """
+    Compare two lists of pucks.
+    Detects if puck names, dewars, OR positions have changed.
+    """
 
-    joined = new_ids - old_ids  # newly added
-    left = old_ids - new_ids    # removed
+    def get_puck_keys(pucks):
+        return {
+            # Including tell_position ensures we sync if a puck moves
+            (p.puck_name, p.dewar_id, getattr(p, "tell_position", None))
+            for p in pucks
+            if getattr(p, "tell_position", None) != "X1"
+        }
+
+    old_keys = get_puck_keys(old)
+    new_keys = get_puck_keys(new)
+
+    joined = new_keys - old_keys
+    left = old_keys - new_keys
 
     return joined, left
 
@@ -317,45 +323,20 @@ def on_sse_event(event):
         handle_tell_change_event()
 
 def on_message(ws, message):
-    #print("[WS][MESSAGE]", message)
     try:
         data = json.loads(message)
-        logger.debug(f"[WS] Received message: {data!r}")
-        if not isinstance(data, list):
-            logger.error(f"[WS] Unexpected message type: {type(data).__name__}")
-            return
-
         new_pucks = [PuckWithTellPosition(**item) for item in data]
-
-        # Keep module-level current_pucks in sync
         global current_pucks
-
-        # First, try to refresh DB/TELL state to avoid overwriting a recent SSE update.
-        try:
-            # This will fetch detected pucks from TELL and update DB via your existing handler
-            handle_tell_change_event()
-            # Small wait gives SSE/DB handler a moment to settle (optional)
-            time.sleep(0.2)
-        except (TellCommunicationError, TellConnectionException, RequestException, ApiException):
-            logger.exception("[WS] Failed to refresh TELL state before websocket update")
-
-        # Compare lists and ignore reference puck at X1 if needed
-        joined, left = compare_and_report_change(current_pucks, new_pucks, lambda p: getattr(p, "puck_name", None))
-
-        # Update local cache
-        current_pucks = new_pucks
-
+        joined, left = compare_and_report_change(current_pucks, new_pucks)
         if joined or left:
-            logger.info(f"[WS] Changes detected joined={joined} left={left}")
-            # Send only when there is a real change
+            logger.info(f"[WS] Changes detected: joined={joined} left={left}")
             ws_update_samples_info(new_pucks)
+            current_pucks = new_pucks
             logger.info("[WS] Sent current pucks state to TELL")
         else:
-            logger.info("[WS] No change; skipping send to TELL")
-    except json.JSONDecodeError:
-        logger.exception("[WS] Failed to decode websocket message as JSON")
-    except (ValidationError, TypeError, ValueError, KeyError):
-        logger.exception("[WS] Failed to process websocket message")
+            logger.info("[WS] No change (same pucks and dewars); skipping send.")
+    except Exception:
+        logger.exception("[WS] Failed to process message")
 
 def on_error(ws, error):
     logger.error(f"[WS] Error: {error}")
@@ -365,6 +346,9 @@ def on_close(ws, close_status_code, close_msg):
 
 def on_open(ws):
     logger.info("[WS] WebSocket opened")
+    global current_pucks
+    # Clear the cache to force a re-sync with the robot on the first message
+    current_pucks = []
 
 
 def main():