Addition: clarify when to expose a required element as invalid (#429)

Co-authored-by: James Craig <cookiecrook@users.noreply.github.com>

index.html

@@ -13907,7 +13907,18 @@ <h4 id=att-required>`required`</h4>
     <tr>
       <th>Comments</th>
       <td>
-        If the element includes both the `required` attribute and the `aria-required` attribute with a valid value, User Agents MUST expose only the `required` attribute value.
+        <p>If the element includes both the `required` attribute and the `aria-required` attribute with a valid value, User Agents MUST expose only the `required` attribute value.</p>
+        <p>
+          If an element is <a data-cite="html/input.html#concept-input-required">required</a>, user agents MUST NOT expose the 
+          element with an intitial invalid state (<a class="core-mapping" href="#ariaInvalidTrue">`aria-invalid="true"`</a>). 
+          The user agent SHOULD expose the invalid state only after <strong>1)</strong> a user has purposefully interacted with a required element, 
+          or attempted to submit a form and <strong>2)</strong> the element, or elements, do not meet
+          <a data-cite="html/form-control-infrastructure.html#constraint-validation">constraint validation</a>.
+        </p>
+        <p>
+          Until these conditions are met, user agents MUST expose the elements as 
+          (<a class="core-mapping" href="#ariaInvalidFalse">`aria-invalid="false"`</a>).
+        </p>
       </td>
     </tr>
   </tbody>
@@ -16730,6 +16741,7 @@ <h3>Change Log</h3>
       <section>
         <h4>Substantive changes since moving to the <a href="https://www.w3.org/WAI/ARIA/">Accessible Rich Internet Applications Working Group</a> (03-Nov-2019)</h4>
         <ul>
+          <li>03-Oct-2023: Clarify when to expose required field as invalid. See <a href="https://github.com/w3c/html-aam/pull/429">GitHub PR 429</a>.</li>
           <li>06-Jun-2023: Add computed roles for all HTML elements. See <a href="https://github.com/w3c/html-aam/pull/465">GitHub PR 465</a>.</li>
           <li>28-Mar-2023: Add `inert` attribute mapping. See <a href="https://github.com/w3c/html-aam/pull/410">GitHub PR 410</a>.</li>
           <li>24-Mar-2023: Add `search` element and its mappings. See <a href="https://github.com/w3c/html-aam/pull/355/">GitHub PR 355</a>.</li>