NimbostratusIt looks like something happening with the big-ip or the network. GARPs being sent in case is virtual server on the big-ip goes up/down or there is a failover from active to standby. By default during failover big-ip generates 5 garps per each virtual IP, self-ip.
I think these need to be investigate more deep. You need to run a packet capture on the big-ip it self to see the packet flow across device. You also need to check ltm logs /var/log/ltm to see if there is any issue mentioned there.
If you are not familiar with big-ip at all you have 2 options.
1) Start learning it. I will take some time 2) Open a case with support. They will tell you what need to be collected and which filters to use for a packet capture.
