Upgrade to 3.1.2

kirby/src/Toolkit/Collection.php

@@ -349,6 +349,9 @@ class Collection extends Iterator implements Countable
 
         foreach ($keys as $key) {
             if ($item = $this->findByKey($key)) {
+                if (is_object($item) && method_exists($item, 'id') === true) {
+                    $key = $item->id();
+                }
                 $result[$key] = $item;
             }
         }

kirby/src/Toolkit/V.php

@@ -71,6 +71,11 @@ class V
             $value = $params[$index] ?? null;
 
             if (is_array($value) === true) {
+                foreach ($value as $index => $item) {
+                    if (is_array($item) === true) {
+                        $value[$index] = implode('|', $item);
+                    }
+                }
                 $value = implode(', ', $value);
             }