diff --git a/conversations.php b/conversations.php
index 007463b..8836a03 100644
--- a/conversations.php
+++ b/conversations.php
@@ -1901,6 +1901,11 @@
             // New: periodic delta poller to fetch only messages newer than last seen timestamp
             async pollNewMessages() {
                 if (!this.currentUserId) return;
+                // Do not run delta polling when a full load is in progress (avoids races/clearing)
+                if (this._fullLoadInProgress) {
+                    if (console && console.debug) console.debug('pollNewMessages skipped due to full load in progress');
+                    return;
+                }
                 try {
                     // If we don't yet have a latest message timestamp, fall back to full load
                     if (!this._latestMessage) {
@@ -2667,6 +2672,8 @@
             async loadMessages(userId, initial = false, follow = true) {
                 if (this.loadingMessages) return;
                 this.loadingMessages = true;
+                // Mark a full load is in progress to avoid race with delta polling
+                this._fullLoadInProgress = true;
                 const container = document.getElementById('chat-conversations');
 
                 // si cargamos más antiguos, preservar scroll
@@ -2893,6 +2900,9 @@
 
                     // Replace media rendering uses window.renderMediaMessage inside element creation/update
 
+                    // Full load finished - unset flag so polling can resume
+                    this._fullLoadInProgress = false;
+
                     if (initial) {
                         this.scrollToBottom();
                     } else if (container) {
@@ -2946,6 +2956,9 @@
                     }
                 } finally {
                     this.loadingMessages = false;
+                    // Ensure the full-load-in-progress flag is cleared even on errors/early returns
+                    try { this._fullLoadInProgress = false; } catch(e) { /* noop */ }
+                    if (console && console.debug) console.debug('loadMessages completed, _fullLoadInProgress cleared');
                 }
             }