diff --git a/src/log.c b/src/log.c
index 7dabe16..b3651cf 100644
--- a/src/log.c
+++ b/src/log.c
@@ -480,7 +480,8 @@
 	cmd[1] = "";
 	cmd_arg = 0;
 
-	expr = sample_parse_expr(cmd, &cmd_arg, curpx->conf.args.file, curpx->conf.args.line, err, &curpx->conf.args, endptr);
+	expr = sample_parse_expr(cmd, &cmd_arg, curpx->conf.args.file, curpx->conf.args.line, err,
+				 (curpx->cap & PR_CAP_DEF) ? NULL: &curpx->conf.args, endptr);
 	if (!expr) {
 		memprintf(err, "failed to parse sample expression <%s> : %s", text, *err);
 		goto error_free;
diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index 1c20f5e..ecc3b88 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -2432,7 +2432,7 @@
 
 				px->conf.args.ctx = ARGC_SRV;
 				port_expr = sample_parse_expr((char *[]){args[cur_arg], NULL}, &idx,
-							      file, line, errmsg, &px->conf.args, NULL);
+							      file, line, errmsg, (px->cap & PR_CAP_DEF) ? NULL: &px->conf.args, NULL);
 
 				if (!port_expr) {
 					memprintf(errmsg, "error detected while parsing port expression : %s", *errmsg);
@@ -3234,7 +3234,7 @@
 			release_sample_expr(status_expr);
 			px->conf.args.ctx = ARGC_SRV;
 			status_expr = sample_parse_expr((char *[]){args[cur_arg], NULL}, &idx,
-							file, line, errmsg, &px->conf.args, NULL);
+							file, line, errmsg, (px->cap & PR_CAP_DEF) ? NULL: &px->conf.args, NULL);
 			if (!status_expr) {
 				memprintf(errmsg, "error detected while parsing status-code expression : %s", *errmsg);
 				goto error;
diff --git a/src/vars.c b/src/vars.c
index 9be146e..130e98b 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -815,7 +815,7 @@
 	}
 
 	rule->arg.vars.expr = sample_parse_expr((char **)args, arg, px->conf.args.file,
-	                                        px->conf.args.line, err, &px->conf.args, NULL);
+	                                        px->conf.args.line, err, (px->cap & PR_CAP_DEF) ? NULL: &px->conf.args, NULL);
 	if (!rule->arg.vars.expr)
 		return ACT_RET_PRS_ERR;