The default markup should not have these issues as of 6.5.0. That said, potentially something is slight amiss in your settings. You can either try resetting them (through the Help tab in the Breadcrumb NavXT settings page), or reference my reply from a similar support thread a while back: https://ww.wp.xz.cn/support/topic/missing-field-itemlistelement-5/#post-14291139
Specifically, check your breadcrumb templates to ensure the “unlinked” templates are similar to the following:
<span property="itemListElement" typeof="ListItem">
<span property="name">%htitle%</span>
<meta property="url" content="%link%">
<meta property="position" content="%position%">
</span>
Commonly, the home breadcrumb template not following this format (%htitle% can be replaced with Home if you wish) can cause the itemListElement error.
