diff --git a/core/archipelago/src/container/prod_orchestrator.rs b/core/archipelago/src/container/prod_orchestrator.rs
index 8ce7f62c..965386d2 100644
--- a/core/archipelago/src/container/prod_orchestrator.rs
+++ b/core/archipelago/src/container/prod_orchestrator.rs
@@ -1230,6 +1230,26 @@ impl ProdContainerOrchestrator {
         if overlaid > 0 {
             tracing::info!("registry catalog overlaid {overlaid} manifest(s) over disk");
         }
+        // The legacy monolithic `mempool` umbrella manifest renders the same
+        // `mempool` container as its split-stack frontend member
+        // `archy-mempool-web`. When the split stack is present, the two render
+        // conflicting quadlet bodies for one container and rewrite+restart each
+        // other forever ("port binding drift"/"network alias drift" loop observed
+        // on catalog-driven .228). The disk-only guard above misses manifests that
+        // arrive via the registry-catalog overlay, so enforce it here over the
+        // merged set: drop the umbrella whenever all three split members exist
+        // (from disk OR catalog). Installing `mempool` assembles the split stack,
+        // so the frontend container is owned by `archy-mempool-web` either way.
+        if ["archy-mempool-db", "mempool-api", "archy-mempool-web"]
+            .iter()
+            .all(|id| state.manifests.contains_key(*id))
+        {
+            if state.manifests.remove("mempool").is_some() {
+                tracing::info!(
+                    "dropped legacy `mempool` umbrella manifest (split mempool stack present) to avoid container ownership conflict with archy-mempool-web"
+                );
+            }
+        }
         Ok(state.manifests.len())
     }