diff --git a/system/src/Grav/Framework/Acl/Access.php b/system/src/Grav/Framework/Acl/Access.php
index 771d58e2f..0a6bb4102 100644
--- a/system/src/Grav/Framework/Acl/Access.php
+++ b/system/src/Grav/Framework/Acl/Access.php
@@ -14,7 +14,6 @@ use Countable;
 use Grav\Common\Utils;
 use IteratorAggregate;
 use JsonSerializable;
-use RuntimeException;
 use Traversable;
 use function count;
 use function is_array;
@@ -79,12 +78,7 @@ class Access implements JsonSerializable, IteratorAggregate, Countable
         $inherited = array_diff_key($parent->getAllActions(), $acl);
 
         $this->inherited += $parent->inherited + array_fill_keys(array_keys($inherited), $name ?? $parent->getName());
-        $acl = array_replace($acl, $inherited);
-        if (null === $acl) {
-            throw new RuntimeException('Internal error');
-        }
-
-        $this->acl = $acl;
+        $this->acl = array_replace($acl, $inherited);
     }
 
     /**
diff --git a/system/src/Grav/Framework/Acl/Action.php b/system/src/Grav/Framework/Acl/Action.php
index 704f61e0d..ee46f55f9 100644
--- a/system/src/Grav/Framework/Acl/Action.php
+++ b/system/src/Grav/Framework/Acl/Action.php
@@ -16,7 +16,6 @@ use IteratorAggregate;
 use RuntimeException;
 use Traversable;
 use function count;
-use function strlen;
 
 /**
  * Class Action
@@ -49,8 +48,8 @@ class Action implements IteratorAggregate, Countable
     {
         $label = $action['label'] ?? null;
         if (!$label) {
-            if ($pos = strrpos($name, '.')) {
-                $label = substr($name, $pos + 1);
+            if ($pos = mb_strrpos($name, '.')) {
+                $label = mb_substr($name, $pos + 1);
             } else {
                 $label = $name;
             }
@@ -115,9 +114,9 @@ class Action implements IteratorAggregate, Countable
      */
     public function getScope(): string
     {
-        $pos = strpos($this->name, '.');
+        $pos = mb_strpos($this->name, '.');
         if ($pos) {
-            return substr($this->name, 0, $pos);
+            return mb_substr($this->name, 0, $pos);
         }
 
         return $this->name;
@@ -128,7 +127,7 @@ class Action implements IteratorAggregate, Countable
      */
     public function getLevels(): int
     {
-        return substr_count($this->name, '.');
+        return mb_substr_count($this->name, '.');
     }
 
     /**
@@ -162,12 +161,12 @@ class Action implements IteratorAggregate, Countable
      */
     public function addChild(Action $child): void
     {
-        if (strpos($child->name, "{$this->name}.") !== 0) {
+        if (mb_strpos($child->name, "{$this->name}.") !== 0) {
             throw new RuntimeException('Bad child');
         }
 
         $child->setParent($this);
-        $name = substr($child->name, strlen($this->name) + 1);
+        $name = mb_substr($child->name, mb_strlen($this->name) + 1);
 
         $this->children[$name] = $child;
     }
diff --git a/system/src/Grav/Framework/Acl/Permissions.php b/system/src/Grav/Framework/Acl/Permissions.php
index 1494b10e1..83c6179ea 100644
--- a/system/src/Grav/Framework/Acl/Permissions.php
+++ b/system/src/Grav/Framework/Acl/Permissions.php
@@ -148,9 +148,6 @@ class Permissions implements ArrayAccess, Countable, IteratorAggregate
     public function addTypes(array $types): void
     {
         $types = array_replace($this->types, $types);
-        if (null === $types) {
-            throw new RuntimeException('Internal error');
-        }
 
         $this->types = $types;
     }
diff --git a/system/src/Grav/Framework/Acl/PermissionsReader.php b/system/src/Grav/Framework/Acl/PermissionsReader.php
index 882050216..5e8e892bb 100644
--- a/system/src/Grav/Framework/Acl/PermissionsReader.php
+++ b/system/src/Grav/Framework/Acl/PermissionsReader.php
@@ -174,9 +174,6 @@ class PermissionsReader
             $scopes[] = $action;
 
             $action = array_replace_recursive(...$scopes);
-            if (null === $action) {
-                throw new RuntimeException('Internal error');
-            }
 
             $newType =  $defaults['type'] ?? null;
             if ($newType && $newType !== $type) {