Seems GL-B1300 has a bug with VPN policies.
While connected on VPN (wireguard) if you remove a device from VPN policy list (which should switch its connection from the VPN tunnel to straight to WAN) it makes such device drop the connection. As a workaround you can toggle VPN policy off and on, and device will now be off VPN policy list and will have connectivity. It is however an annoying bug.
Can someone at GL-inet look into this. Thanks