Hi Chris and Jason thanks for your response.
In our case we have trunked the F5 ports on our cisco switches but we havent enabled Spanning Tree port fast on the switch ports and F5 is currently running spanning tree instance
I have heard this issue from my predecessor so I am unable to check logs to findout if this triggered STP
Probably we should enable Spanning Tree port fast on the cisco switches to prevent this
Also I have seen the ARP issue in an other environment. I had forced the unit 1 to be standby and the unit 2 took over and when I pushed the unit 2 back to standby then unit 1 became active but clients were not able to reach our VIPs from outside and we had to clear ARP on our firewall to fix the issue
I have few other questions regarding Redundancy State Preference as well. I will ask them in a different thread
Thanks,
Chandru