diff --git a/lib/Context/Context.php b/lib/Context/Context.php
index df45dc6..4ae2e87 100644
--- a/lib/Context/Context.php
+++ b/lib/Context/Context.php
@@ -9,6 +9,7 @@ namespace JKingWeb\Arsse\Context;
 use JKingWeb\Arsse\Misc\Date;
 
 class Context extends ExclusionContext {
+    /** @var ExclusionContext */
     public $not;
     public $reverse = false;
     public $limit = 0;
diff --git a/lib/Context/ExclusionContext.php b/lib/Context/ExclusionContext.php
index 6a662f2..b2954e3 100644
--- a/lib/Context/ExclusionContext.php
+++ b/lib/Context/ExclusionContext.php
@@ -32,9 +32,9 @@ class ExclusionContext {
 
     public function __clone() {
         if ($this->parent) {
-            $p = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT, 2)[1]['object'] ?? null;
-            if ($p instanceof self) {
-                $this->parent = $p;
+            $t = debug_backtrace(\DEBUG_BACKTRACE_IGNORE_ARGS | \DEBUG_BACKTRACE_PROVIDE_OBJECT, 2)[1];
+            if (($t['object'] ?? null) instanceof self && $t['function'] === "__clone") {
+                $this->parent = $t['object'];
             }
         }
     }