If you haven't provided that information from the new ISP router...but that's not related to OpenWrt. I would verify that not that you have this new ISP that you actually have public IP address.
Or...you can say it only works for the single IP you set (e.g. you setup a personal webserver on your desktop, and test from the desktop)...but sure, call it "broken".
As I noted:
This works exactly as people desire (I assume those calling it a bug need the developers to identify exactly what each person else wishes to redirect - besides the IP itself, without creating a security hole).