diff --git a/src/BacktraceProcessor.php b/src/BacktraceProcessor.php
index 36165ee..eebcf24 100644
--- a/src/BacktraceProcessor.php
+++ b/src/BacktraceProcessor.php
@@ -34,7 +34,7 @@ public function __invoke(LogRecord $record): LogRecord
             }
 
             $class = $call['class'] ?? null;
-            if (\str_contains($file, self::MONOLOG_VENDOR_DIRNAME) || \str_starts_with($class, 'MonologProcessorCollection\\')) {
+            if (\str_contains($file, self::MONOLOG_VENDOR_DIRNAME) || null !== $class && \str_starts_with($class, 'MonologProcessorCollection\\')) {
                 continue;
             }