Zone cellular base port PPP bug

Ok really odd one

VPN300 V5.36(ABFC.1)

I have a USB Huawei E303 its IP is 192.168.8.100 I make zone cellular1

On ge4 I have a Nighthawk M2 Mobile Router set to DHCP gets a 10. IP with its zone being cellular1.

I have hideipvpn with PPP setup for L2TP base port ge4 (interesting you can't use a USB cellular) zone test

I have a routing rule LAN1 on ge3 for client 192.168.255.193 to use hideipvpn ping 1.1.1.1

What happens is the PPP looks to connect...in a odd way where it uses the USB cellular not out ge4 pings go out ge4 as 192.168.8.100 not 10.

When I disable USB or set cellular zone to none then PPP works.