diff --git a/subst.c b/subst.c
index 1dbfb5e..049962e 100644
--- a/subst.c
+++ b/subst.c
@@ -5011,7 +5011,8 @@ process_substitute (string, open_for_read_in_child)
 
 #if defined (JOB_CONTROL)
   old_pipeline_pgrp = pipeline_pgrp;
-  pipeline_pgrp = shell_pgrp;
+  if (pipeline_pgrp == 0 || (subshell_environment & (SUBSHELL_PIPE|SUBSHELL_FORK|SUBSHELL_ASYNC)) == 0)
+    pipeline_pgrp = shell_pgrp;
   save_pipeline (1);
 #endif /* JOB_CONTROL */
 
-- 
2.9.3