Feed URLs throwing warnings in the PHP log

[aussig]

Feed URLs such as https://www.opensceneryx.com/objects/vegetation/quercus/12/28m/feed/ are throwing errors like:

PHP Warning:  call_user_func_array() expects parameter 1 to be a valid callback, first array member is not a valid class name or object in [path redacted]/wp/wp-includes/class-wp-hook.php on line 286

There are two issues here:

1. Feed URLs should not be exposed for these pages as there are no feeds
2. Fix this warning if it occurs