Warning regarding "wdp_sitemap_walker" appears on all pages, affecting content

Hi there,

After our most recent update to WordPress 5.2.1 and our Enfold update to 4.5.5, we have noticed some breaking on our staging site. The follow error appears on all pages above the header:

Warning: Declaration of wdp_sitemap_walker::start_el(&$output, $item, $depth, $args) should be compatible with Walker_Nav_Menu::start_el(&$output, $item, $depth = 0, $args = Array, $id = 0) in /nas/content/staging/binarystream/wp-content/themes/binarystream/php/functions_eric.php on line 987

There is also many issues regarding the content. The header appears to be gigantic and spills off the page, and headers to certain content blocks have been replaced with “[block]1[/block]”, “[block]2[/block]”, “[block]3[/block]”…

This issue is really affecting our ability to make new changes to the site, as our staging site was our main vehicle for this. Is there anything that can be done here?

Cheers,
Bradley