diff --git a/availability/condition/group/classes/condition.php b/availability/condition/group/classes/condition.php
index 39050603269..2445cdc963f 100644
--- a/availability/condition/group/classes/condition.php
+++ b/availability/condition/group/classes/condition.php
@@ -176,6 +176,12 @@ class condition extends \core_availability\condition {
     public function filter_user_list(array $users, $not, \core_availability\info $info,
             \core_availability\capability_checker $checker) {
         global $CFG, $DB;
+
+        // If the array is empty already, just return it.
+        if (!$users) {
+            return $users;
+        }
+
         require_once($CFG->libdir . '/grouplib.php');
         $course = $info->get_course();
 
diff --git a/availability/condition/grouping/classes/condition.php b/availability/condition/grouping/classes/condition.php
index a538704b38f..e0b59976ba8 100644
--- a/availability/condition/grouping/classes/condition.php
+++ b/availability/condition/grouping/classes/condition.php
@@ -209,6 +209,11 @@ class condition extends \core_availability\condition {
             \core_availability\capability_checker $checker) {
         global $CFG, $DB;
 
+        // If the array is empty already, just return it.
+        if (!$users) {
+            return $users;
+        }
+
         // List users for this course who match the condition.
         $groupingusers = $DB->get_records_sql("
                 SELECT DISTINCT gm.userid
diff --git a/availability/condition/profile/classes/condition.php b/availability/condition/profile/classes/condition.php
index 0007e8751fc..59d06175ee1 100644
--- a/availability/condition/profile/classes/condition.php
+++ b/availability/condition/profile/classes/condition.php
@@ -416,6 +416,11 @@ class condition extends \core_availability\condition {
             \core_availability\capability_checker $checker) {
         global $CFG, $DB;
 
+        // If the array is empty already, just return it.
+        if (!$users) {
+            return $users;
+        }
+
         // Get all users from the list who match the condition.
         list ($sql, $params) = $DB->get_in_or_equal(array_keys($users));