R46 and R77 failing on th with role="rowheader"

[dan-tripp-siteimprove]

On my "base example" below, R46 and R77 are failing. I think that they should pass - that is, if I'm reading ARIA in HTML correctly, where it says "If the ancestor table element is exposed as a role=table, then columnheader, rowheader and cell are allowed..." Of course, next it says "... but NOT RECOMMENDED". At any rate:

<h2>Base example.  From customer page.  Cells in top row fail R46 and R77.</h2>
<table>
	<tbody>
		<tr>
			<th role="rowheader">a</th>
			<td>b</td>
			<td>c</td>
		</tr>
		<tr>
			<td colspan="3">d</td>
		</tr>
	</tbody>
</table>

<h2>Base example + bottom row removed.  Cells in top row pass R46 and R77.</h2>
<table>
	<tbody>
		<tr>
			<th role="rowheader">a</th>
			<td>b</td>
			<td>c</td>
		</tr>
		<!--
		<tr>
			<td colspan="3">d</td>
		</tr>
		-->
	</tbody>
</table>

<h2>Base example + bottom row given a th with scope="row".  Cells in top row pass R46 and R77.</h2>
<table>
	<tbody>
		<tr>
			<th role="rowheader">a</th>
			<td>b</td>
			<td>c</td>
		</tr>
		<tr>
			<th scope="row">d</th>
			<td>e</td>
			<td>f</td>
		</tr>
	</tbody>
</table>

<h2>Base example + bottom row colspan removed.  Cells in top row still fail R46 and R77.</h2>
<table>
	<tbody>
		<tr>
			<th role="rowheader">a</th>
			<td>b</td>
			<td>c</td>
		</tr>
		<tr>
			<td zzzcolspan="3">d</td>
		</tr>
	</tbody>
</table>

<h2>Base example + role="rowheader" replaced with scope="row".  Cells in top row pass R46 and R77.</h2>
<table>
	<tbody>
		<tr>
			<th zzzrole="rowheader" scope="row">a</th>
			<td>b</td>
			<td>c</td>
		</tr>
		<tr>
			<td colspan="3">d</td>
		</tr>
	</tbody>
</table>