diff --git a/hide-engine.js b/hide-engine.js
index 9416621..f01f310 100644
--- a/hide-engine.js
+++ b/hide-engine.js
@@ -12,6 +12,8 @@ const hideState = {
   operationVersion: 0,
 };
 
+const BME_HIDE_HASH_MARKER = "__st_bme_hide_managed";
+
 function getTimerApi(runtime = {}) {
   const rawSetTimeout =
     typeof runtime.setTimeout === "function"
@@ -179,6 +181,12 @@ function restoreManagedSystemFlags(chat, runtime = {}) {
     const message = chat[index];
     if (!message || message.is_system !== true) continue;
     message.is_system = false;
+    if (message.extra && typeof message.extra === "object") {
+      delete message.extra[BME_HIDE_HASH_MARKER];
+      if (Object.keys(message.extra).length === 0) {
+        delete message.extra;
+      }
+    }
     restored.push(index);
   }
 
@@ -195,6 +203,10 @@ function markManagedSystemRange(chat, start, end, runtime = {}) {
     const message = chat[index];
     if (!message || message.is_system === true) continue;
     message.is_system = true;
+    const extra =
+      message.extra && typeof message.extra === "object" ? message.extra : {};
+    extra[BME_HIDE_HASH_MARKER] = true;
+    message.extra = extra;
     hideState.managedSystemIndices.add(index);
     marked.push(index);
   }
diff --git a/runtime-state.js b/runtime-state.js
index 4fc02ec..0def616 100644
--- a/runtime-state.js
+++ b/runtime-state.js
@@ -208,10 +208,15 @@ export function stableHashString(text) {
 }
 
 export function buildMessageHash(message) {
+  const managedHideMarker = Boolean(
+    message?.extra &&
+      typeof message.extra === "object" &&
+      message.extra.__st_bme_hide_managed === true,
+  );
   const swipeId = Number.isFinite(message?.swipe_id) ? message.swipe_id : null;
   const payload = JSON.stringify({
     isUser: Boolean(message?.is_user),
-    isSystem: Boolean(message?.is_system),
+    isSystem: managedHideMarker ? false : Boolean(message?.is_system),
     text: String(message?.mes || ""),
     swipeId,
   });
diff --git a/tests/runtime-history.mjs b/tests/runtime-history.mjs
index 142182d..aeb4e02 100644
--- a/tests/runtime-history.mjs
+++ b/tests/runtime-history.mjs
@@ -51,6 +51,24 @@ const editedDetection = detectHistoryMutation(editedChat, {
 assert.equal(editedDetection.dirty, true);
 assert.equal(editedDetection.earliestAffectedFloor, 1);
 
+const bmeHiddenChat = structuredClone(chat);
+bmeHiddenChat[1].is_system = true;
+bmeHiddenChat[1].extra = { __st_bme_hide_managed: true };
+const bmeHiddenDetection = detectHistoryMutation(bmeHiddenChat, {
+  lastProcessedAssistantFloor: 3,
+  processedMessageHashes: hashes,
+});
+assert.equal(bmeHiddenDetection.dirty, false);
+
+const realSystemFlipChat = structuredClone(chat);
+realSystemFlipChat[1].is_system = true;
+const realSystemFlipDetection = detectHistoryMutation(realSystemFlipChat, {
+  lastProcessedAssistantFloor: 3,
+  processedMessageHashes: hashes,
+});
+assert.equal(realSystemFlipDetection.dirty, true);
+assert.equal(realSystemFlipDetection.earliestAffectedFloor, 1);
+
 const truncatedChat = chat.slice(0, 2);
 const truncatedDetection = detectHistoryMutation(truncatedChat, {
   lastProcessedAssistantFloor: 3,