Outlook mail deletes <a> tag, when <a> tag has no href

Question

<a style="background: rgb(80, 80, 80); border: 5px solid transparent; border-radius: 5px; text-align: center; padding: 0px; width: 150px; height: 30px;">
	<span>Text</span>
</a>

With the <a> tag without href, when sending to Outlook mail (Outlook web), the <a> tag will be removed. This will cause the button to not display, only displaying text, the above phenomenon also occurs in the Outlook app in Microsoft Office 2021.

This phenomenon does not occur in other mail apps, and I cannot find any documentation that talks about this issue. So I want to confirm that when the <a> tag does not have href, Outlook will remove the <a> tag, is that correct ?

Thanks.