As the title says, adding port ranges under Firewall → Port Forwards in the GL.iNet Admin Panel does not yield any results to the iptables.
I confirmed via the advanced Luci interface that any rules created in the GL.iNet Admin Panel were not listed at all under /cgi-bin/luci/admin/network/firewall/forwards/.
The workaround is to create the rules via the advanced Luci interface and not use the GL.iNet Admin Panel.
Issue was reproduced on 3.027 and 3.100 with multiple configuration resets.
Has anyone else experienced this or something similar? My network setup is very simple, with a mesh of 3 wired GL-B1300 routers and a single modem with a public IP.