diff --git a/changelog.md b/changelog.md
index 746140f..3b697eb 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,12 @@
 # Changelog
 
+## 2026-03-24 - 11.10.4 - fix(monitoring)
+handle multiple protocol cache entries per backend in metrics output
+
+- Group detected protocol cache entries by backend host and port so multiple domain-specific records are preserved.
+- Emit one backend metrics row per cached domain and avoid dropping unmatched protocol cache entries by tracking seen entries with a composite host:port:domain key.
+- Use cached protocol values when available while keeping backend-only rows for metrics without protocol cache data.
+
 ## 2026-03-23 - 11.10.3 - fix(deps)
 bump tstest, smartmetrics, and taskbuffer to latest patch releases
 
diff --git a/ts/00_commitinfo_data.ts b/ts/00_commitinfo_data.ts
index 93175ae..e12a1f9 100644
--- a/ts/00_commitinfo_data.ts
+++ b/ts/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/dcrouter',
-  version: '11.10.3',
+  version: '11.10.4',
   description: 'A multifaceted routing service handling mail and SMS delivery functions.'
 }
diff --git a/ts/monitoring/classes.metricsmanager.ts b/ts/monitoring/classes.metricsmanager.ts
index fa029b5..85b5e5d 100644
--- a/ts/monitoring/classes.metricsmanager.ts
+++ b/ts/monitoring/classes.metricsmanager.ts
@@ -595,47 +595,84 @@ export class MetricsManager {
       const backendMetrics = proxyMetrics.backends.byBackend();
       const protocolCache = proxyMetrics.backends.detectedProtocols();
 
-      // Index protocol cache by "host:port"
-      const cacheByKey = new Map<string, (typeof protocolCache)[number]>();
+      // Group protocol cache entries by host:port so we can match them to backend metrics.
+      // The protocol cache is keyed by (host, port, domain) in Rust, so the same host:port
+      // can have multiple entries for different domains.
+      const cacheByBackend = new Map<string, (typeof protocolCache)[number][]>();
       for (const entry of protocolCache) {
-        cacheByKey.set(`${entry.host}:${entry.port}`, entry);
+        const backendKey = `${entry.host}:${entry.port}`;
+        let entries = cacheByBackend.get(backendKey);
+        if (!entries) {
+          entries = [];
+          cacheByBackend.set(backendKey, entries);
+        }
+        entries.push(entry);
       }
 
       const backends: Array<any> = [];
-      const seen = new Set<string>();
+      const seenCacheKeys = new Set<string>();
 
       for (const [key, bm] of backendMetrics) {
-        seen.add(key);
-        const cache = cacheByKey.get(key);
-        backends.push({
-          backend: key,
-          domain: cache?.domain ?? null,
-          protocol: bm.protocol,
-          activeConnections: bm.activeConnections,
-          totalConnections: bm.totalConnections,
-          connectErrors: bm.connectErrors,
-          handshakeErrors: bm.handshakeErrors,
-          requestErrors: bm.requestErrors,
-          avgConnectTimeMs: Math.round(bm.avgConnectTimeMs * 10) / 10,
-          poolHitRate: Math.round(bm.poolHitRate * 1000) / 1000,
-          h2Failures: bm.h2Failures,
-          h2Suppressed: cache?.h2Suppressed ?? false,
-          h3Suppressed: cache?.h3Suppressed ?? false,
-          h2CooldownRemainingSecs: cache?.h2CooldownRemainingSecs ?? null,
-          h3CooldownRemainingSecs: cache?.h3CooldownRemainingSecs ?? null,
-          h2ConsecutiveFailures: cache?.h2ConsecutiveFailures ?? null,
-          h3ConsecutiveFailures: cache?.h3ConsecutiveFailures ?? null,
-          h3Port: cache?.h3Port ?? null,
-          cacheAgeSecs: cache?.ageSecs ?? null,
-        });
+        const cacheEntries = cacheByBackend.get(key);
+        if (!cacheEntries || cacheEntries.length === 0) {
+          // No protocol cache entry — emit one row with backend metrics only
+          backends.push({
+            backend: key,
+            domain: null,
+            protocol: bm.protocol,
+            activeConnections: bm.activeConnections,
+            totalConnections: bm.totalConnections,
+            connectErrors: bm.connectErrors,
+            handshakeErrors: bm.handshakeErrors,
+            requestErrors: bm.requestErrors,
+            avgConnectTimeMs: Math.round(bm.avgConnectTimeMs * 10) / 10,
+            poolHitRate: Math.round(bm.poolHitRate * 1000) / 1000,
+            h2Failures: bm.h2Failures,
+            h2Suppressed: false,
+            h3Suppressed: false,
+            h2CooldownRemainingSecs: null,
+            h3CooldownRemainingSecs: null,
+            h2ConsecutiveFailures: null,
+            h3ConsecutiveFailures: null,
+            h3Port: null,
+            cacheAgeSecs: null,
+          });
+        } else {
+          // One row per domain, each enriched with the shared backend metrics
+          for (const cache of cacheEntries) {
+            const compositeKey = `${cache.host}:${cache.port}:${cache.domain ?? ''}`;
+            seenCacheKeys.add(compositeKey);
+            backends.push({
+              backend: key,
+              domain: cache.domain ?? null,
+              protocol: cache.protocol ?? bm.protocol,
+              activeConnections: bm.activeConnections,
+              totalConnections: bm.totalConnections,
+              connectErrors: bm.connectErrors,
+              handshakeErrors: bm.handshakeErrors,
+              requestErrors: bm.requestErrors,
+              avgConnectTimeMs: Math.round(bm.avgConnectTimeMs * 10) / 10,
+              poolHitRate: Math.round(bm.poolHitRate * 1000) / 1000,
+              h2Failures: bm.h2Failures,
+              h2Suppressed: cache.h2Suppressed,
+              h3Suppressed: cache.h3Suppressed,
+              h2CooldownRemainingSecs: cache.h2CooldownRemainingSecs,
+              h3CooldownRemainingSecs: cache.h3CooldownRemainingSecs,
+              h2ConsecutiveFailures: cache.h2ConsecutiveFailures,
+              h3ConsecutiveFailures: cache.h3ConsecutiveFailures,
+              h3Port: cache.h3Port,
+              cacheAgeSecs: cache.ageSecs,
+            });
+          }
+        }
       }
 
       // Include protocol cache entries with no matching backend metric
       for (const entry of protocolCache) {
-        const key = `${entry.host}:${entry.port}`;
-        if (!seen.has(key)) {
+        const compositeKey = `${entry.host}:${entry.port}:${entry.domain ?? ''}`;
+        if (!seenCacheKeys.has(compositeKey)) {
           backends.push({
-            backend: key,
+            backend: `${entry.host}:${entry.port}`,
             domain: entry.domain,
             protocol: entry.protocol,
             activeConnections: 0,
diff --git a/ts_web/00_commitinfo_data.ts b/ts_web/00_commitinfo_data.ts
index 93175ae..e12a1f9 100644
--- a/ts_web/00_commitinfo_data.ts
+++ b/ts_web/00_commitinfo_data.ts
@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@serve.zone/dcrouter',
-  version: '11.10.3',
+  version: '11.10.4',
   description: 'A multifaceted routing service handling mail and SMS delivery functions.'
 }