XF 2.3 message_macros template modification

[Anatoliy]

For some time I have an add-on that does several template modifications. It worked fine until I upgraded to 2.3.2. After that Google Search Console started to show me a bunch of 'missing field name (in author ). And it looks like the reason is a template modification that unlinks usernames for guest:

Find:

/<h4 class="message-name"><xf:username user(.*)<\/h4>/isU

Replace:

<xf:if is="!$xf.visitor.user_id">
    <div class="message-name myUsername">{$fallbackName}</div>
<xf:else />
    $0
</xf:if>

How should I edit it so it would not produce those errors?