If the unit is covered by a support contract and this is service impacting, your best bet is to open a support case to investigate the issue live.
Most common reason for a unit to behave like this is if you have a VLAN failover enabled, and unit has the monitored links down. I haven't seen this specific evidence in your logs, but you do have a deamon heartbeat failure error. That means a system process is failing to respond to HA daemon heartbeat messages, which triggers the failover.
Again, I'd suggest you have support look into this.
Any resolution?? We have bigip LTM 14.1 and it's been doing this for 24 hours now, but it's this exact situation. How did you fix it?? We do have a vLan failover ..Been waiting for 24 hours from f5 support with no resolution in sight .