diff --git a/ext/pulse/pulsesink.c b/ext/pulse/pulsesink.c
index 63d361af5d..85c488ad61 100644
--- a/ext/pulse/pulsesink.c
+++ b/ext/pulse/pulsesink.c
@@ -2088,6 +2088,7 @@ out:
 
   pa_threaded_mainloop_unlock (mainloop);
 
+  gst_caps_replace (&spec.caps, NULL);
   gst_object_unref (pbuf);
 
 done: