Ok,
Firstly , out of personal experience I don't recommend messing around with generators unless you have the experience, patience and time,
Second, how many persons have the access for the generator? is it only you? or there is many people have the access?
Your problem is either electrical or mechanical,
If it's mechanical that means the generator temperature is at critical levels and the cooling system needs maintenance ( here PLEASE do not do it yourself unless you are qualified )
If it's electrical, that means the temerature sensor is either needs re-adjusment or replacement, also check the control unit settings, there is a big chance (if you are not the only one has the access for generators) that someone messed with control settings,
Anyway, refer to the manual and check if your problem is mentioned there,
Regards