Fix for filtering collections throwing null key error

CHANGELOG.md

@@ -14,6 +14,7 @@
     * Fix for lightbox media function throwing error [#981](https://github.com/getgrav/grav/issues/981)
     * Removed 307 redirect code option as it is not well supported [#743](https://github.com/getgrav/grav-plugin-admin/issues/743)
     * Fixed issue with folders with name `*.md` are not confused with pages [#995](https://github.com/getgrav/grav/issues/995)
+    * Fixed an issue when filtering collections causing null key
 
 # v1.1.2
 ## 08/10/2016

system/src/Grav/Common/Page/Page.php

@@ -2235,7 +2235,7 @@ class Page
                             if (empty($page->taxonomy[$taxonomy]) || !in_array(htmlspecialchars_decode($item,
                                     ENT_QUOTES), $page->taxonomy[$taxonomy])
                             ) {
-                                $collection->remove();
+                                $collection->remove($page->path());
                             }
                         }
                     }