So not being able to figure out an actual solution, I did put together a band-aid. So far so good as I haven't found a way to break it. Maybe this can help someone else who runs into the same issue.

In includes/templates/myrcclone/common/tpl_main_page.php I modified the breadcrumb output...

original
PHP Code:
<!-- bof  breadcrumb -->
<?php if (!$breadcrumb->isEmpty() && (DEFINE_BREADCRUMB_STATUS == '1' || (DEFINE_BREADCRUMB_STATUS == '2' && !$this_is_home_page))) { ?>
    <div id="navBreadCrumb"><?php echo $breadcrumb->trail(BREAD_CRUMBS_SEPARATOR); ?></div>
<?php ?>
<!-- eof breadcrumb -->
band-aid
PHP Code:
<!-- bof  breadcrumb -->


<?php if (!$breadcrumb->isEmpty() && (DEFINE_BREADCRUMB_STATUS == '1' || (DEFINE_BREADCRUMB_STATUS == '2' && !$this_is_home_page))) {
        
$clean_breadcrumbs $breadcrumb->trail(BREAD_CRUMBS_SEPARATOR);
        if(
strpos($breadcrumb->trail(BREAD_CRUMBS_SEPARATOR),'//.html')){
            
$clean_breadcrumbs preg_replace('/\/\/\.html/'''$breadcrumb->trail(BREAD_CRUMBS_SEPARATOR));
        }
    
?>
    <div id="navBreadCrumb"><?php echo $clean_breadcrumbs?></div>
<?php ?>
<!-- eof breadcrumb -->
Best regards,
John