diff --git a/lib/extension/networkMap.ts b/lib/extension/networkMap.ts
index 13cd6e2b2..a88dfa32b 100644
--- a/lib/extension/networkMap.ts
+++ b/lib/extension/networkMap.ts
@@ -268,8 +268,7 @@ export default class NetworkMap extends Extension {
                 networkAddress: device.zh.networkAddress,
                 manufacturerName: device.zh.manufacturerName,
                 modelID: device.zh.modelID,
-                // biome-ignore lint/style/noNonNullAssertion: TODO: biome migration: wrong typing? will be undefined if type=EndDevice?
-                failed: failed.get(device)!,
+                failed: failed.get(device),
                 lastSeen: device.zh.lastSeen,
                 definition,
             });
diff --git a/lib/types/api.ts b/lib/types/api.ts
index 71603155f..e1e025acb 100644
--- a/lib/types/api.ts
+++ b/lib/types/api.ts
@@ -263,7 +263,7 @@ export interface Zigbee2MQTTNetworkMap {
         networkAddress: number;
         manufacturerName: string | undefined;
         modelID: string | undefined;
-        failed: string[];
+        failed?: string[];
         lastSeen: number | undefined;
         definition?: {model: string; vendor: string; supports: string; description: string};
     }[];