Incorrect display since the penultimate update

It appears that is_singular() is not returning true on that page. Since the code that checks that in Breadcrumb NavXT hasn’t changed in over 2 years, I’m not sure if Breadcrumb NavXT 5.3.0 broke this. What is doing your filtering (setting it up on the back end)? If that is provided by a plugin, is it possible something changed there?

Problems like this usually occur when something modified the $post variable in a custom loop and does not restore it to its initial value when done. One way of checking would be to try placing the breadcrumb trail higher up in the page (before the loop, and any secondary loops), and if you get the expected result then the the problem is the $post variable has been modified. You can also try placing wp_reset_query() before the call to bcn_display(), just note this can not be done if bcn_display() is within the loop (will cause an infinite loop).