BIG-IP Peer self local IP cannot be ping

Hi Expert,

I have a big-ip in HA setting.

But if I am in primary one, I cannot ping peer local self IP.

I can ping primary local and floating IP. 

https://my.f5.com/manage/s/article/K3475

I check this link, and I do tcpdump in primary one, I can see I am using primary local self IP as source IP.

In peer one tcpdump, I can see 

12:14:59.719138 ARP, Request who-has 172.166.94.174 tell 172.166.94.163, length 48 out slot1/tmm2 lis=

It seems the ARP not completed, so it should fix in network side or BIG-IP? 

172.166.94.174 is my gateway and 172.166.94.163 is peer local self ip

In primary one tcpdump, I can see below:

12:19:48.827770 ARP, Request who-has 172.166.94.163 tell 172.166.94.162, length 48 out slot1/tmm1 lis=

172.166.94.162 is my loca self ip