EX7000 - when it starts up it relays clients MAC, but on main router reboot, EX7000 then uses VAC

Hi,

I use static reservations on main router, based on client MAC. My EX7000 relays the client MAC to router when it starts up, but if main router reboots, the EX7000 then decides to relay VAC, not MAC - this is throwing off my static assignment.

Is there any way to force EX7000 to use either MAC or VAC for its clients?

Thanks