sunny-se · Aug 10, 2026
diff --git a/lib/core/base/context.js b/lib/core/base/context.js
@@ -118,6 +118,12 @@ function isPageContext({ include }) {
 function validateContext(context) {
   if (context.include.length === 0 && context.frames.length === 0) {
     const env = respondable.isInFrame() ? 'frame' : 'page';
+    // [a11y-core]: debug logging for empty-include investigation
+    (Function("return this")()).console.error('[DEBUG-ISSUE] empty include context', {
+      env,
+      t: Math.round(performance.now()),
+      url: location.href
+    });
     throw new Error('No elements found for include in ' + env + ' Context');
   }
 }

diff --git a/lib/core/public/run-rules.js b/lib/core/public/run-rules.js
@@ -21,6 +21,12 @@ import log from '../log';
  * @param  {Function} reject   Called when execution failed, receives (err : Error)
  */
 export default function runRules(context, options, resolve, reject) {
+  // [a11y-core]: debug logging for run lifecycle
+  (Function("return this")()).console.debug('[DEBUG-ISSUE] axe.runRules start', {
+    t: Math.round(performance.now()),
+    running: axe._running,
+    inFrame: window.top !== window
+  });
   try {
     context = new Context(context);
     axe._tree = context.flatTree;

diff --git a/lib/core/public/teardown.js b/lib/core/public/teardown.js
@@ -5,6 +5,19 @@ import { resetGlobals } from './run/globals-setup';
  * Clean up axe-core tree and caches. `axe.run` will call this function at the end of the run so there's no need to call it yourself afterwards.
  */
 function teardown() {
+  // [a11y-core]: debug logging for teardown race investigation
+  if (axe._running) {
+    (Function("return this")()).console.warn('[DEBUG-ISSUE] axe.teardown() WHILE RUN IN FLIGHT', {
+      t: Math.round(performance.now()),
+      inFrame: window.top !== window
+    }, new Error().stack);
+  } else {
+    (Function("return this")()).console.debug('[DEBUG-ISSUE] axe.teardown()', {
+      t: Math.round(performance.now()),
+      running: axe._running,
+      inFrame: window.top !== window
+    });
+  }
   // Reset MUST to happen before the cache is cleared
   resetGlobals();
   axe._memoizedFns.forEach(fn => fn.clear());

diff --git a/lib/core/utils/collect-results-from-frames.js b/lib/core/utils/collect-results-from-frames.js
@@ -44,7 +44,15 @@ export default function collectResultsFromFrames(
         return res({ results, frameElement });
       }
 
-      sendCommandToFrame(frameElement, params, callback, rej);
+      // [a11y-core]: debug logging for frame rejection path
+      sendCommandToFrame(frameElement, params, callback, (err) => {
+        (Function("return this")()).console.error('[DEBUG-ISSUE] frame error — rejecting full run', {
+          frame: frameElement && (frameElement.id || frameElement.src),
+          error: err && err.message,
+          t: Math.round(performance.now())
+        });
+        rej(err);
+      });
     });
   });
 

diff --git a/lib/core/utils/get-selector.js b/lib/core/utils/get-selector.js
@@ -353,7 +353,14 @@ function getThreeLeastCommonFeatures(elm, selectorData) {
 function generateSelector(elm, options, doc) {
   /*eslint no-loop-func:0*/
   // TODO: es-modules_selectorData
+  // [a11y-core]: debug logging for teardown race investigation
   if (!axe._selectorData) {
+    (Function("return this")()).console.error('[DEBUG-ISSUE] _selectorData missing', {
+      t: Math.round(performance.now()),
+      running: axe._running,
+      inFrame: window.top !== window,
+      url: location.href
+    }, new Error().stack);
     throw new Error('Expect axe._selectorData to be set up');
   }
   const { toRoot = false } = options;

diff --git a/lib/core/utils/send-command-to-frame.js b/lib/core/utils/send-command-to-frame.js
@@ -28,6 +28,12 @@ export default function sendCommandToFrame(node, parameters, resolve, reject) {
     // This double timeout is important for allowing iframes to respond
     // DO NOT REMOVE
     timeout = setTimeout(() => {
+      // [a11y-core]: debug logging for frame ping failure
+      (Function("return this")()).console.warn('[DEBUG-ISSUE] frame ping failed (no axe in frame)', {
+        frame: node && (node.id || node.src || node.name),
+        debug: parameters.debug,
+        t: Math.round(performance.now())
+      });
       if (!parameters.debug) {
         resolve(null);
       } else {
@@ -48,6 +54,11 @@ function callAxeStart(node, parameters, resolve, reject) {
   const frameWaitTime = parameters.options?.frameWaitTime ?? 60000;
   const win = node.contentWindow;
   const timeout = setTimeout(function collectResultFramesTimeout() {
+    // [a11y-core]: debug logging for frame timeout
+    (Function("return this")()).console.error('[DEBUG-ISSUE] frame timed out', {
+      frame: node && (node.id || node.src || node.name),
+      t: Math.round(performance.now())
+    });
     reject(err('Axe in frame timed out', node));
   }, frameWaitTime);