diff --git a/system/presence/thingsonmymind.md b/system/presence/thingsonmymind.md
index 3f46fd5..ab3955c 100644
--- a/system/presence/thingsonmymind.md
+++ b/system/presence/thingsonmymind.md
@@ -81,6 +81,15 @@ Heartbeats complete but don't appear where expected. Are they going to a differe
 **Update (8:43 PM):**  
 **CRITICAL DISCOVERY (8:44 PM):**  
 Found `lettabot-agent.json` -- heartbeats ARE routing to `conv-9896e32e-b7c9-4793-b4b0-faabe5ca0aba` (same as DM room). But my API query showed NO heartbeat messages in that conversation. Hypothesis: heartbeat messages may be:
+**DEEPER MYSTERY (9:33 PM):**  
+Examined heartbeat.ts code - it sends user messages via `bot.sendToAgent()`. But API query shows conversation `conv-9896e32e-b7c9-4793-b4b0-faabe5ca0aba` has NO `user_message` types since March 9! Only `tool_return`, `approval_response`, `reasoning`, `approval_request` messages. 
+
+Either:
+1. Heartbeats stopped firing after March 9 (but logs say `heartbeat_completed`)
+2. Heartbeat messages aren't being persisted as `user_message`
+3. Heartbeats are going to a DIFFERENT conversation entirely
+
+This is a database/API layer mystery. Need to check raw Letta database or logs.
 1. Using different message type not visible in standard query
 2. Being filtered by the API
 3. Deleted/overwritten immediately