diff --git a/app/client/aclui/AccessRules.ts b/app/client/aclui/AccessRules.ts
index e205bce1..afe04df5 100644
--- a/app/client/aclui/AccessRules.ts
+++ b/app/client/aclui/AccessRules.ts
@@ -1322,7 +1322,7 @@ class SpecialSchemaObsRuleSet extends SpecialObsRuleSet {
   protected _buildDomWarning(): DomContents {
     return dom.maybe(
       (use) => use(this._body).every(rule => rule.isBuiltInOrEmpty(use)),
-      () => cssConditionError({style: 'margin-left: 56px; margin-bottom: 8px;'},
+      () => cssError(
         t("This default should be changed if editors' access is to be limited. "),
         dom('a', {style: 'color: inherit; text-decoration: underline'},
           'Dismiss', dom.on('click', () => this._allowEditors('confirm'))),
@@ -1969,10 +1969,17 @@ const cssInput = styled(textInput, `
   }
 `);
 
+const cssError = styled('div', `
+  color: ${theme.errorText};
+  margin-left: 56px;
+  margin-bottom: 8px;
+  margin-top: 4px;
+`);
+
 const cssConditionError = styled('div', `
+  color: ${theme.errorText};
   margin-top: 4px;
   width: 100%;
-  color: ${theme.errorText};
 `);
 
 /**
diff --git a/app/client/models/errors.ts b/app/client/models/errors.ts
index ad39f368..7ca826a4 100644
--- a/app/client/models/errors.ts
+++ b/app/client/models/errors.ts
@@ -70,17 +70,32 @@ export function reportSuccess(msg: MessageType, options?: Partial<INotifyOptions
   return reportMessage(msg, {level: 'success', ...options});
 }
 
-// Errors from cross-origin scripts, and some add-ons, show up as unhelpful sanitized "Script
-// error." messages. We want to know if they occur, but they are useless to the user, and useless
-// to report multiple times. We report them just once to the server.
-//
-// In particular, this addresses a bug on iOS version of Firefox, which produces uncaught
-// sanitized errors on load AND on attempts to report them, leading to a loop that hangs the
-// browser. Reporting just once is a sufficient workaround.
 function isUnhelpful(ev: ErrorEvent) {
-  return !ev.filename && !ev.lineno && ev.message?.toLowerCase().includes('script error');
+  if (ev.message === 'ResizeObserver loop completed with undelivered notifications.') {
+    // Sometimes on Chrome, changing the browser zoom level causes this benign error to
+    // be thrown. It seems to only appear on the Access Rules page, and may have something
+    // to do with Ace. In any case, the error seems harmless and it isn't particularly helpful,
+    // so we don't report it more than once. A quick Google search for the error message
+    // produces many reports, although at the time of this comment, none seem to be related
+    // to Ace, so there's a chance something else is amiss.
+    return true;
+  }
+
+  if (!ev.filename && !ev.lineno && ev.message?.toLowerCase().includes('script error')) {
+    // Errors from cross-origin scripts, and some add-ons, show up as unhelpful sanitized "Script
+    // error." messages. We want to know if they occur, but they are useless to the user, and useless
+    // to report multiple times. We report them just once to the server.
+    //
+    // In particular, this addresses a bug on iOS version of Firefox, which produces uncaught
+    // sanitized errors on load AND on attempts to report them, leading to a loop that hangs the
+    // browser. Reporting just once is a sufficient workaround.
+    return true;
+  }
+
+  return false;
 }
-let unhelpfulErrors = 0;
+
+const unhelpfulErrors = new Set<string>();
 
 /**
  * Report an error to the user using the global Notifier instance. If the argument is a UserError
@@ -99,8 +114,9 @@ export function reportError(err: Error|string, ev?: ErrorEvent): void {
   if (ev && isUnhelpful(ev)) {
     // Report just once to the server. There is little point reporting subsequent such errors once
     // we know they happen, since each individual error has no useful information.
-    if (++unhelpfulErrors <= 1) {
+    if (!unhelpfulErrors.has(ev.message)) {
       logError(err);
+      unhelpfulErrors.add(ev.message);
     }
     return;
   }