I have a bunch of these:
/var/log/ltm:Mar 20 09:51:49 dcsltm01 notice sod[4708]: 010c002a:5: Requesting tmm to resend gratuitous arps for traffic group /Common/traffic-group-1.
/var/log/ltm:Mar 20 11:11:32 dcsltm01 notice sod[4708]: 010c002a:5: Requesting tmm to resend gratuitous arps for traffic group /Common/traffic-group-1.
/var/log/ltm:Mar 20 13:59:47 dcsltm01 notice sod[4708]: 010c002a:5: Requesting tmm to resend gratuitous arps for traffic group /Common/traffic-group-1.
I think the only time it would request a device send a gratuitous arp is when a failure has occured, or would you expect more info?