Investigating a bigip reboot from LTM logs

There should be more info about the reboot in the logs. The reboot conditions, on v11.6.4, are as follows:

# tmsh show /sys ha-status all-properties 
-------------------------------------------------------------------------------------------------------------------------------------------------------
Sys::HA Status
Slot  Feature               Key                                        Action                        Fail  Feature  Take  Client  Proc          Timeout
                                                                                                           Enabled  Act   Data                  (sec)
-------------------------------------------------------------------------------------------------------------------------------------------------------
...
1     nic-failsafe          tmm                                        reboot                        no    yes      no    0       tmm           0
1     nic-failsafe          tmm1                                       reboot                        no    yes      no    0       tmm1          0
1     nic-failsafe          tmm2                                       reboot                        no    yes      no    0       tmm2          0
1     nic-failsafe          tmm3                                       reboot                        no    yes      no    0       tmm3          0
1     nic-failsafe          tmm4                                       reboot                        no    yes      no    0       tmm4          0
1     nic-failsafe          tmm5                                       reboot                        no    yes      no    0       tmm5          0
1     nic-failsafe          tmm6                                       reboot                        no    yes      no    0       tmm6          0
1     nic-failsafe          tmm7                                       reboot                        no    yes      no    0       tmm7          0
1     nic-failsafe          tmm8                                       reboot                        no    yes      no    0       tmm8          0
1     nic-failsafe          tmm9                                       reboot                        no    yes      no    0       tmm9          0
1     reboot-request        sod                                        reboot                        no    yes      no    0       sod           0
1     software-update       lind                                       reboot                        no    yes      no    0       lind          0

. Not sure about your situation.