diff --git a/common/ports.tf b/common/ports.tf
index 27f8207..a603624 100644
--- a/common/ports.tf
+++ b/common/ports.tf
@@ -9,12 +9,12 @@ locals {
 
   p_fields = ["from", "to", "proto", "description", "cidr"]
   #  p_map    = length(var.ingress_port_list) > 0 ? [for p in local.ports : zipmap(local.p_fields, p)] : var.ingress_port_map
-  p_map    = length(var.ingress_port_list) > 0 ? [for p in collapse(concat(local.ports, var.ingress_port_list)) : zipmap(local.p_fields, p)] : [for p in local.ports : zipmap(local.p_fields, p)]
-  port_map = { "external" = collapse(concat(local.p_map, var.ingress_port_map)) }
+  p_map    = length(var.ingress_port_list) > 0 ? [for p in compact(concat(local.ports, var.ingress_port_list)) : zipmap(local.p_fields, p)] : [for p in local.ports : zipmap(local.p_fields, p)]
+  port_map = { "external" = compact(concat(local.p_map, var.ingress_port_map)) }
 
   p_self_fields  = ["from", "to", "proto", "description"]
   self_port_list = length(var.ingress_self_port_list) > 0 ? [for p in var.ingress_self_port_list : zipmap(local.p_self_fields, p)] : local._defaults["self_port_list"]
-  self_port_map  = collapse(concat(local.self_port_list, var.ingress_self_port_map))
+  self_port_map  = compact(concat(local.self_port_list, var.ingress_self_port_map))
 }
 
 # locals {
diff --git a/custom/ports.tf b/custom/ports.tf
index 8b8a90f..64ff02b 100644
--- a/custom/ports.tf
+++ b/custom/ports.tf
@@ -9,9 +9,9 @@ locals {
 
   p_fields = ["from", "to", "proto", "description", "cidr"]
   p_map    = length(var.ingress_port_list) > 0 ? [for p in local.ports : zipmap(local.p_fields, p)] : var.ingress_port_map
-  port_map = { "external" = collapse(concat(local.p_map, var.ingress_port_map)) }
+  port_map = { "external" = compact(concat(local.p_map, var.ingress_port_map)) }
 
   p_self_fields  = ["from", "to", "proto", "description"]
   self_port_list = length(var.ingress_self_port_list) > 0 ? [for p in var.ingress_self_port_list : zipmap(local.p_self_fields, p)] : local._defaults["self_port_list"]
-  self_port_map  = collapse(concat(local.self_port_list, var.ingress_self_port_map))
+  self_port_map  = compact(concat(local.self_port_list, var.ingress_self_port_map))
 }
diff --git a/sas/ports.tf b/sas/ports.tf
index 7a2630a..b9bfc01 100644
--- a/sas/ports.tf
+++ b/sas/ports.tf
@@ -43,9 +43,9 @@ locals {
   p_fields = ["from", "to", "proto", "description", "cidr"]
   #  p_map    = length(var.ingress_port_list) > 0 ? [for p in local.ports : zipmap(local.p_fields, p)] : var.ingress_port_map
   p_map    = length(var.ingress_port_list) > 0 ? [for p in concat(local.ports, var.ingress_port_list) : zipmap(local.p_fields, p)] : [for p in local.ports : zipmap(local.p_fields, p)]
-  port_map = { "external" = collapse(concat(local.p_map, var.ingress_port_map)) }
+  port_map = { "external" = compact(concat(local.p_map, var.ingress_port_map)) }
 
   p_self_fields  = ["from", "to", "proto", "description"]
   self_port_list = length(var.ingress_self_port_list) > 0 ? [for p in var.ingress_self_port_list : zipmap(local.p_self_fields, p)] : local._defaults["self_port_list"]
-  self_port_map  = collapse(concat(local.self_port_list, var.ingress_self_port_map))
+  self_port_map  = compact(concat(local.self_port_list, var.ingress_self_port_map))
 }