diff --git a/ext/iodine/fio.c b/ext/iodine/fio.c
index afa7880..74cbe0e 100644
--- a/ext/iodine/fio.c
+++ b/ext/iodine/fio.c
@@ -1025,7 +1025,7 @@ static void fio_defer_thread_wait(void) {
     if (fio_defer_has_queue())
       pthread_setspecific(static_throttle_key, (void *)1);
     else if (static_throttle < FIO_DEFER_THROTTLE_LIMIT)
-      pthread_setspecific(static_throttle_key, (void *)(static_throttle << 1));
+      pthread_setspecific(static_throttle_key, (void *)((static_throttle << 1) | 1));
   }
 }
 
diff --git a/lib/iodine/version.rb b/lib/iodine/version.rb
index 250b1f6..e9baf67 100644
--- a/lib/iodine/version.rb
+++ b/lib/iodine/version.rb
@@ -1,3 +1,3 @@
 module Iodine
-  VERSION = '0.7.50'.freeze
+  VERSION = '0.7.51'.freeze
 end