diff --git a/reportbuilder/classes/local/helpers/user_profile_fields.php b/reportbuilder/classes/local/helpers/user_profile_fields.php
index 9991a77f0f6..5067ae24287 100644
--- a/reportbuilder/classes/local/helpers/user_profile_fields.php
+++ b/reportbuilder/classes/local/helpers/user_profile_fields.php
@@ -155,8 +155,9 @@ class user_profile_fields {
                 $columnfieldsql = $DB->sql_order_by_text($columnfieldsql, 1024);
             }
 
-            $columns[] = (new column(
-                'profilefield_' . core_text::strtolower($profilefield->field->shortname),
+            $columnname = 'profilefield_' . core_text::strtolower($profilefield->field->shortname);
+            $columns[$columnname] = (new column(
+                $columnname,
                 new lang_string('customfieldcolumn', 'core_reportbuilder', $profilefield->display_name(false)),
                 $this->entityname
             ))
@@ -176,7 +177,7 @@ class user_profile_fields {
                 ->set_is_available($profilefield->is_visible());
         }
 
-        return $columns;
+        return array_values($columns);
     }
 
     /**
@@ -221,9 +222,10 @@ class user_profile_fields {
                     break;
             }
 
+            $filtername = 'profilefield_' . core_text::strtolower($profilefield->field->shortname);
             $filter = (new filter(
                 $classname,
-                'profilefield_' . core_text::strtolower($profilefield->field->shortname),
+                $filtername,
                 new lang_string('customfieldcolumn', 'core_reportbuilder', $profilefield->display_name(false)),
                 $this->entityname,
                 $fieldsql,
@@ -238,10 +240,10 @@ class user_profile_fields {
                 $filter->set_options_callback(fn(): array => $profilefield->options);
             }
 
-            $filters[] = $filter;
+            $filters[$filtername] = $filter;
         }
 
-        return $filters;
+        return array_values($filters);
     }
 
     /**
diff --git a/reportbuilder/tests/local/helpers/user_profile_fields_test.php b/reportbuilder/tests/local/helpers/user_profile_fields_test.php
index 8301b98ae5d..06c2cde55cf 100644
--- a/reportbuilder/tests/local/helpers/user_profile_fields_test.php
+++ b/reportbuilder/tests/local/helpers/user_profile_fields_test.php
@@ -91,6 +91,13 @@ class user_profile_fields_test extends core_reportbuilder_testcase {
             $userentity->get_entity_name(),
         ))->get_columns();
 
+        // Create a field which will duplicate one of the subsequently generated fields (case-insensitive shortname).
+        $this->getDataGenerator()->create_custom_profile_field([
+            'shortname' => 'CHECKBOX',
+            'name' => 'Duplicate checkbox field',
+            'datatype' => 'checkbox',
+        ]);
+
         // Add new custom profile fields.
         $userprofilefields = $this->generate_userprofilefields();
 
@@ -210,6 +217,13 @@ class user_profile_fields_test extends core_reportbuilder_testcase {
             $userentity->get_entity_name(),
         ))->get_filters();
 
+        // Create a field which will duplicate one of the subsequently generated fields (case-insensitive shortname).
+        $this->getDataGenerator()->create_custom_profile_field([
+            'shortname' => 'CHECKBOX',
+            'name' => 'Duplicate checkbox field',
+            'datatype' => 'checkbox',
+        ]);
+
         // Add new custom profile fields.
         $userprofilefields = $this->generate_userprofilefields();