diff --git a/extensions/telegram/src/doctor.test.ts b/extensions/telegram/src/doctor.test.ts
index 96e999578a35..af8fa7aa830b 100644
--- a/extensions/telegram/src/doctor.test.ts
+++ b/extensions/telegram/src/doctor.test.ts
@@ -5,12 +5,14 @@ import {
   collectTelegramApiRootWarnings,
   collectTelegramEmptyAllowlistExtraWarnings,
   collectTelegramGroupPolicyWarnings,
+  collectTelegramMalformedGroupsWarnings,
   collectTelegramMissingEnvTokenWarnings,
   collectTelegramSelectedQuoteToolProgressWarnings,
   maybeRepairTelegramApiRoots,
   maybeRepairTelegramAllowFromUsernames,
   scanTelegramBotEndpointApiRoots,
   scanTelegramInvalidAllowFromEntries,
+  scanTelegramMalformedGroupsConfig,
   scanTelegramSelectedQuoteToolProgressWarnings,
   telegramDoctor,
 } from "./doctor.js";
@@ -206,6 +208,42 @@ describe("telegram doctor", () => {
     ).toHaveLength(1);
   });
 
+  it("warns when Telegram groups use a non-object shape", async () => {
+    const cfg = {
+      channels: {
+        telegram: {
+          groups: ["-1001234567890"],
+          accounts: {
+            work: {
+              groups: null,
+            },
+          },
+        },
+      },
+    } as unknown as OpenClawConfig;
+
+    const hits = scanTelegramMalformedGroupsConfig(cfg);
+    expect(hits).toEqual([
+      { path: "channels.telegram.groups", actualType: "array" },
+      { path: "channels.telegram.accounts.work.groups", actualType: "null" },
+    ]);
+
+    const warnings = collectTelegramMalformedGroupsWarnings({
+      hits,
+      doctorFixCommand: "openclaw doctor --fix",
+    });
+    expect(warnings[0]).toContain("object map keyed by Telegram group/chat id");
+    expect(warnings[1]).toContain('channels.telegram.groups."-1001234567890".topics."99"');
+    expect(warnings[1]).toContain("openclaw doctor --fix");
+
+    expect(
+      await telegramDoctor.collectPreviewWarnings?.({
+        cfg,
+        doctorFixCommand: "openclaw doctor --fix",
+      }),
+    ).toEqual(expect.arrayContaining(warnings));
+  });
+
   it("repairs @username entries to numeric ids", async () => {
     lookupTelegramChatIdMock.mockResolvedValue("111");
 
diff --git a/extensions/telegram/src/doctor.ts b/extensions/telegram/src/doctor.ts
index 2876fb2fd9a9..d1da958d6e2d 100644
--- a/extensions/telegram/src/doctor.ts
+++ b/extensions/telegram/src/doctor.ts
@@ -26,6 +26,7 @@ import {
 import { resolveTelegramPreviewStreamMode } from "./preview-streaming.js";
 
 type TelegramAllowFromInvalidHit = { path: string; entry: string };
+type TelegramMalformedGroupsHit = { path: string; actualType: string };
 type TelegramSelectedQuoteToolProgressHit = { path: string; replyToMode: string };
 type TelegramApiRootBotEndpointHit = {
   path: string;
@@ -131,6 +132,53 @@ function collectTelegramAllowFromLists(
   return refs;
 }
 
+function describeConfigValueType(value: unknown): string {
+  if (Array.isArray(value)) {
+    return "array";
+  }
+  if (value === null) {
+    return "null";
+  }
+  return typeof value;
+}
+
+export function scanTelegramMalformedGroupsConfig(
+  cfg: OpenClawConfig,
+): TelegramMalformedGroupsHit[] {
+  const hits: TelegramMalformedGroupsHit[] = [];
+  for (const scope of collectTelegramAccountScopes(cfg)) {
+    if (!Object.prototype.hasOwnProperty.call(scope.account, "groups")) {
+      continue;
+    }
+    const groups = scope.account.groups;
+    if (asObjectRecord(groups)) {
+      continue;
+    }
+    hits.push({
+      path: `${scope.prefix}.groups`,
+      actualType: describeConfigValueType(groups),
+    });
+  }
+  return hits;
+}
+
+export function collectTelegramMalformedGroupsWarnings(params: {
+  hits: TelegramMalformedGroupsHit[];
+  doctorFixCommand: string;
+}): string[] {
+  if (params.hits.length === 0) {
+    return [];
+  }
+  const sample = params.hits[0] ?? {
+    path: "channels.telegram.groups",
+    actualType: "unknown",
+  };
+  return [
+    `- ${sanitizeForLog(sample.path)} has invalid Telegram groups shape (${sanitizeForLog(sample.actualType)}); expected an object map keyed by Telegram group/chat id, not an array, string, or null.`,
+    `- Example shape: channels.telegram.groups."-1001234567890".topics."99" = { agentId: "support" }. Use topics for forum-topic routing, then rerun ${params.doctorFixCommand} for any remaining Telegram config cleanup.`,
+  ];
+}
+
 export function scanTelegramInvalidAllowFromEntries(
   cfg: OpenClawConfig,
 ): TelegramAllowFromInvalidHit[] {
@@ -557,6 +605,10 @@ export const telegramDoctor: ChannelDoctorAdapter = {
   normalizeCompatibilityConfig: normalizeTelegramCompatibilityConfig,
   collectPreviewWarnings: ({ cfg, doctorFixCommand, env }) => [
     ...collectTelegramMissingEnvTokenWarnings({ cfg, env }),
+    ...collectTelegramMalformedGroupsWarnings({
+      hits: scanTelegramMalformedGroupsConfig(cfg),
+      doctorFixCommand,
+    }),
     ...collectTelegramInvalidAllowFromWarnings({
       hits: scanTelegramInvalidAllowFromEntries(cfg),
       doctorFixCommand,
diff --git a/src/config/validation.channel-metadata.test.ts b/src/config/validation.channel-metadata.test.ts
index aa6e18e88469..6ad607299a3f 100644
--- a/src/config/validation.channel-metadata.test.ts
+++ b/src/config/validation.channel-metadata.test.ts
@@ -246,6 +246,28 @@ describe("validateConfigObjectRawWithPlugins channel metadata", () => {
 
     expect(result.ok).toBe(true);
   });
+
+  it("keeps raw channel validation diagnostics plugin-agnostic", () => {
+    const result = validateConfigObjectRawWithPlugins({
+      channels: {
+        telegram: {
+          groups: ["-1001234567890"],
+        },
+      },
+    });
+
+    expect(result.ok).toBe(false);
+    if (!result.ok) {
+      expect(result.issues).toContainEqual(
+        expect.objectContaining({
+          path: "channels.telegram.groups",
+          message: expect.stringContaining("invalid config:"),
+        }),
+      );
+      expect(result.issues[0]?.message).not.toContain("Telegram groups");
+      expect(result.issues[0]?.message).not.toContain("openclaw doctor --fix");
+    }
+  });
 });
 
 describe("validateConfigObjectRawWithPlugins plugin config defaults", () => {
diff --git a/src/config/validation.ts b/src/config/validation.ts
index eb2527423743..2a7144d6fc25 100644
--- a/src/config/validation.ts
+++ b/src/config/validation.ts
@@ -231,6 +231,9 @@ function collectAllowedValuesFromBundledChannelSchemaPath(
   return collectAllowedValuesFromJsonSchemaNode(targetNode);
 }
 
+function formatRawChannelConfigIssueMessage(message: string): string {
+  return `invalid config: ${message}`;
+}
 function collectRawBundledChannelConfigIssues(config: OpenClawConfig): ConfigValidationIssue[] {
   if (!config.channels || !isRecord(config.channels)) {
     return [];
@@ -253,10 +256,11 @@ function collectRawBundledChannelConfigIssues(config: OpenClawConfig): ConfigVal
       const message = error.additionalProperty
         ? `${error.message}: "${error.additionalProperty}"`
         : error.message;
+      const path =
+        error.path === "<root>" ? `channels.${channelId}` : `channels.${channelId}.${error.path}`;
       issues.push({
-        path:
-          error.path === "<root>" ? `channels.${channelId}` : `channels.${channelId}.${error.path}`,
-        message: `invalid config: ${message}`,
+        path,
+        message: formatRawChannelConfigIssueMessage(message),
         allowedValues: error.allowedValues,
         allowedValuesHiddenCount: error.allowedValuesHiddenCount,
       });
@@ -1401,10 +1405,11 @@ function validateConfigObjectWithPluginsBase(
       });
       if (!result.ok) {
         for (const error of result.errors) {
+          const path =
+            error.path === "<root>" ? `channels.${trimmed}` : `channels.${trimmed}.${error.path}`;
           issues.push({
-            path:
-              error.path === "<root>" ? `channels.${trimmed}` : `channels.${trimmed}.${error.path}`,
-            message: `invalid config: ${error.message}`,
+            path,
+            message: formatRawChannelConfigIssueMessage(error.message),
             allowedValues: error.allowedValues,
             allowedValuesHiddenCount: error.allowedValuesHiddenCount,
           });