Hello,
Why do you mean seems to be getting ARP request?
How did you saw that,
If you evern ping from the Standby unit or from the router to the standby IP the IP to MAC Resolution will happen and ofcourse you will see the entry in the ARP table of the router.
Regards
Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC