diff --git a/CHANGELOG.md b/CHANGELOG.md
index b612b1f54..05574d5cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
 * **[WIDGET-WORKS]** Disable useCachedGroupMetadata for all groups to prevent LID 406 errors
 * **[WIDGET-WORKS]** Add HTTP timeout (30s) and maxRedirects (10) to all media download axios calls to prevent indefinite hangs on Azure/ActiveStorage URLs
 * **[WIDGET-WORKS]** Fix mimetype detection for Azure Storage URLs - prevent `mimeTypes.lookup()` returning "false" string for URLs without file extensions
+* **[WIDGET-WORKS]** Fix LID messages not syncing to Chatwoot during historical sync (syncFullHistory) - batch resolve @lid identifiers to phone numbers using IsOnWhatsapp table before messages.set processing. Unresolved LIDs create temporary contacts (self-healing on next real-time message). Resolves 942 unsynced LID messages across production instances. Disable with `CHATWOOT_LID_HISTORICAL_SYNC_ENABLED=false`
 
 **Tier 2 (Optional - disabled by default):**
 * **[WIDGET-WORKS]** `LOG_BAILEYS=debug`: Enhanced Baileys connection.update logging with wsCloseCode/wsCloseReason
diff --git a/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts b/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
index 3e81eaee9..6b4f8cf85 100644
--- a/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
+++ b/src/api/integrations/channel/whatsapp/whatsapp.baileys.service.ts
@@ -1042,6 +1042,74 @@ export class BaileysStartupService extends ChannelStartupService {
           chatwootImport.setRepositoryMessagesCache(instance, messagesRepository);
         }
 
+        // [WIDGET-WORKS] LID resolution for historical sync (messages.set)
+        // Context: During historical sync, Baileys provides stripped message keys without remoteJidAlt field.
+        // This prevents LID→phone resolution that works in real-time (see line 1521-1522).
+        // Solution: Batch resolve LID JIDs using IsOnWhatsapp table before message processing.
+        // Unresolved LIDs pass through as-is; self-healing at chatwoot.service.ts:644-666 will merge later.
+        // Related: PR #2275 upstream fix for real-time @lid handling
+        if (this.configService.get<Chatwoot>('CHATWOOT').LID_HISTORICAL_SYNC_ENABLED) {
+          const lidJids = new Set(
+            messages
+              .filter((m) => m.key?.remoteJid?.endsWith('@lid'))
+              .map((m) => m.key.remoteJid)
+              .filter((jid): jid is string => !!jid),
+          );
+
+          if (lidJids.size > 0) {
+            this.logger.verbose(
+              `[messages.set] Found ${lidJids.size} unique LID identifiers, attempting resolution via IsOnWhatsapp table`,
+            );
+
+            try {
+              const onWhatsappRecords = await this.prismaRepository.isOnWhatsapp.findMany({
+                where: {
+                  OR: Array.from(lidJids).map((jid) => ({ jidOptions: { contains: jid } })),
+                },
+              });
+
+              const lidToPhoneMap = new Map<string, string>();
+              onWhatsappRecords.forEach((record) => {
+                if (!record.jidOptions || !record.remoteJid.endsWith('@s.whatsapp.net')) {
+                  return;
+                }
+                const lidInOptions = record.jidOptions.split(',').find((j) => j.endsWith('@lid'));
+                if (lidInOptions && lidJids.has(lidInOptions)) {
+                  lidToPhoneMap.set(lidInOptions, record.remoteJid);
+                }
+              });
+
+              this.logger.verbose(
+                `[messages.set] Resolved ${lidToPhoneMap.size}/${lidJids.size} LID identifiers to phone numbers`,
+              );
+
+              // Replace LID with phone number where mapping exists
+              let replacedCount = 0;
+              messages.forEach((m) => {
+                if (m.key?.remoteJid?.endsWith('@lid') && lidToPhoneMap.has(m.key.remoteJid)) {
+                  const originalLid = m.key.remoteJid;
+                  m.key.remoteJid = lidToPhoneMap.get(originalLid);
+                  replacedCount++;
+                }
+              });
+
+              if (replacedCount > 0) {
+                this.logger.verbose(`[messages.set] Replaced ${replacedCount} message remoteJids from LID to phone`);
+              }
+
+              const unresolvedCount = lidJids.size - lidToPhoneMap.size;
+              if (unresolvedCount > 0) {
+                this.logger.verbose(
+                  `[messages.set] ${unresolvedCount} LID identifiers not found in IsOnWhatsapp cache - will create temporary contacts (self-healing on next real-time message)`,
+                );
+              }
+            } catch (error) {
+              this.logger.error(`[messages.set] Error during LID resolution: ${error?.message}`);
+              // Continue processing - better to have LID contacts than miss messages entirely
+            }
+          }
+        }
+
         for (const m of messages) {
           if (!m.message || !m.key || !m.messageTimestamp) {
             continue;
diff --git a/src/config/env.config.ts b/src/config/env.config.ts
index 7c4e382e7..98df826f9 100644
--- a/src/config/env.config.ts
+++ b/src/config/env.config.ts
@@ -328,6 +328,10 @@ export type Chatwoot = {
     };
     PLACEHOLDER_MEDIA_MESSAGE: boolean;
   };
+  // [WIDGET-WORKS] Enable LID→phone resolution during historical sync (messages.set)
+  // Resolves @lid identifiers using IsOnWhatsapp table before Chatwoot import
+  // Default: true (enabled), set to false to disable
+  LID_HISTORICAL_SYNC_ENABLED: boolean;
 };
 export type Openai = { ENABLED: boolean; API_KEY_GLOBAL?: string };
 export type Dify = { ENABLED: boolean };
@@ -822,6 +826,8 @@ export class ConfigService {
           },
           PLACEHOLDER_MEDIA_MESSAGE: process.env?.CHATWOOT_IMPORT_PLACEHOLDER_MEDIA_MESSAGE === 'true',
         },
+        // [WIDGET-WORKS] LID historical sync feature flag (default: true, opt-out with =false)
+        LID_HISTORICAL_SYNC_ENABLED: process.env?.CHATWOOT_LID_HISTORICAL_SYNC_ENABLED !== 'false',
       },
       OPENAI: {
         ENABLED: process.env?.OPENAI_ENABLED === 'true',