diff --git a/src/netlist.c b/src/netlist.c
index eb84aff0..7ddce21b 100644
--- a/src/netlist.c
+++ b/src/netlist.c
@@ -638,14 +638,35 @@ static void name_pass_through_nets()
   Str_hashentry *table[17];
   Str_hashentry *entry;
   const char *pin_name;
+  int *pt_symbol = NULL; /* pass-through symbols, symbols with duplicated ports */
+  int there_are_pt = 0;
 
   xctx->hash_size = 17;
+  pt_symbol = my_calloc(1573, xctx->symbols, sizeof(int));
+  for(i = 0; i < xctx->symbols; i++) {
+    memset(table, 0, xctx->hash_size * sizeof(Str_hashentry *));
+    for(j = 0; j < xctx->sym[i].rects[PINLAYER]; j++) {
+      const char *pin_name = get_tok_value(xctx->sym[i].rect[PINLAYER][j].prop_ptr, "name", 0);
+      entry = str_hash_lookup(table, pin_name, "1", XINSERT_NOREPLACE);
+      if(entry) {
+        pt_symbol[i] = 1;
+        there_are_pt = 1;
+      }
+    }
+    if(pt_symbol[i]) dbg(1, "duplicated pins: %s\n", xctx->sym[i].name);
+  }
+  str_hash_free(table);
+  if(!there_are_pt) { /* nothing to do: no pass through symbols */
+    my_free(1573, &pt_symbol);
+    return;
+  }
   do { /* keep looping until propagation of nets occurs */
     changed = 0;
     memset(table, 0, xctx->hash_size * sizeof(Str_hashentry *));
     for (i=0;i<instances;i++) {
       dbg(1, "instance %d: %s\n", i, inst[i].instname);
       if(inst[i].ptr<0) continue;
+      if(!pt_symbol[ inst[i].ptr ]) continue;
       my_strdup(1565, &type, (inst[i].ptr + xctx->sym)->type);
       if (type && !IS_LABEL_OR_PIN(type) ) {
         if ((rects = (inst[i].ptr+ xctx->sym)->rects[PINLAYER]) > 0) {
@@ -735,6 +756,7 @@ static void name_pass_through_nets()
   } while(changed);
   my_free(1570, &type);
   my_free(1571, &type2);
+  my_free(1572, &pt_symbol);
   xctx->hash_size = HASHSIZE;
 }
 
diff --git a/xschem_library/examples/doublepin.sch b/xschem_library/examples/doublepin.sch
index 877caa58..846d667e 100644
--- a/xschem_library/examples/doublepin.sch
+++ b/xschem_library/examples/doublepin.sch
@@ -1,4 +1,5 @@
-v {xschem version=3.0.0 file_version=1.2 }
+v {xschem version=3.1.0 file_version=1.2
+}
 G {}
 K {}
 V {
@@ -17,11 +18,7 @@ always begin
   A=~A;
   if(i==20) $finish;
 end}
-S {va a 0 pwl 0 0 100n 0 101n 3
-vvcc vcc 0 dc 3
-vvss vss 0 dc 0
-
-.tran 1n 200n}
+S {}
 E {}
 C {title.sym} 160 -30 0 0 {name=l1 author="Stefan Schippers"}
 C {ipin.sym} 210 -220 0 0 {name=p1 lab=A}
diff --git a/xschem_library/examples/test_doublepin.sch b/xschem_library/examples/test_doublepin.sch
index 423613ac..49eefc5f 100644
--- a/xschem_library/examples/test_doublepin.sch
+++ b/xschem_library/examples/test_doublepin.sch
@@ -58,19 +58,29 @@ lab=AA}
 N 450 -1110 600 -1110 {
 lab=BB}
 N 450 -410 600 -410 {
-lab=#net1}
+lab=RRSSTT}
 N 450 -390 600 -390 {
-lab=#net2}
+lab=CCKK}
 N 450 -370 600 -370 {
-lab=#net3}
+lab=AA}
 N 450 -350 600 -350 {
-lab=#net4}
+lab=BB}
 N 450 -310 480 -310 {
 lab=ZZ7}
 N 900 -310 930 -310 {
 lab=ZZ8}
-C {title.sym} 160 -30 0 0 {name=l1 author="Stefan Schippers"}
-C {doublepin.sym} 300 -610 0 0 {name=x1}
+N 900 -410 1050 -410 {
+lab=RRSSTT}
+N 900 -390 1050 -390 {
+lab=CCKK}
+N 900 -370 1050 -370 {
+lab=AA}
+N 900 -350 1050 -350 {
+lab=BB}
+N 1350 -310 1380 -310 {
+lab=ZZ9}
+C {doublepin.sym} 1200 -360 0 0 {name=x9}
+C {doublepin.sym} 750 -360 0 0 {name=x8}
 C {doublepin.sym} 750 -610 0 0 {name=x2}
 C {lab_wire.sym} 520 -620 0 0 {name=l2 sig_type=std_logic lab=AA}
 C {lab_pin.sym} 480 -560 0 1 {name=p3 lab=ZZ5}
@@ -106,16 +116,18 @@ C {lab_wire.sym} 520 -1130 0 0 {name=l22 sig_type=std_logic lab=AA}
 C {lab_wire.sym} 520 -1170 0 0 {name=l23 sig_type=std_logic lab=RRSSTT}
 C {lab_wire.sym} 520 -1150 0 0 {name=l24 sig_type=std_logic lab=CCKK}
 C {lab_wire.sym} 520 -1110 0 0 {name=l25 sig_type=std_logic lab=BB}
-C {doublepin.sym} 300 -360 0 0 {name=x7}
-C {doublepin.sym} 750 -360 0 0 {name=x8}
+C {lab_pin.sym} 150 -350 0 0 {name=l33 sig_type=std_logic lab=BB}
+C {doublepin.sym} 300 -610 0 0 {name=x1}
 C {lab_pin.sym} 480 -310 0 1 {name=p7 lab=ZZ7}
 C {lab_pin.sym} 930 -310 0 1 {name=p8 lab=ZZ8}
 C {lab_pin.sym} 150 -370 0 0 {name=l30 sig_type=std_logic lab=AA}
 C {lab_pin.sym} 150 -410 0 0 {name=l31 sig_type=std_logic lab=RRSSTT}
 C {lab_pin.sym} 150 -390 0 0 {name=l32 sig_type=std_logic lab=CCKK}
-C {lab_pin.sym} 150 -350 0 0 {name=l33 sig_type=std_logic lab=BB}
+C {doublepin.sym} 300 -360 0 0 {name=x7}
 C {ipin.sym} 100 -80 0 0 { name=p9 lab=RRSSTT }
 C {ipin.sym} 100 -100 0 0 { name=p10 lab=CCKK }
 C {ipin.sym} 100 -120 0 0 { name=p11 lab=BB }
 C {ipin.sym} 100 -140 0 0 { name=p12 lab=AA }
-C {opin.sym} 270 -120 0 0 { name=p13 lab=ZZ[8..1]}
+C {opin.sym} 270 -120 0 0 { name=p13 lab=ZZ[9..1]}
+C {title.sym} 160 -30 0 0 {name=l1 author="Stefan Schippers"}
+C {lab_pin.sym} 1380 -310 0 1 {name=p8 lab=ZZ9}