trying a whole new approach, seems like it worked on my wit-vm-router-config package, lets see what it does here ...

debian/wit-network-config.postinst

@@ -17,6 +17,10 @@ set -xe
 # for details, see https://www.debian.org/doc/debian-policy/ or
 # the debian-policy package
 
+
+#DEBHELPER#
+
+
 case "$1" in
     configure)
 
@@ -398,9 +402,5 @@ case "$1" in
     ;;
 esac
 
-# dh_installdeb will replace this with shell code automatically
-# generated by other debhelper scripts.
-
-#DEBHELPER#
 
 exit 0