[PROBLEM] Some settings not saved correctly

[the_bertrum]

But, now it pops-up that I reboot my wireless router every day at 5 AM...

My Pi3 threw a lot of information into /var/log/syslog when the router did it's thing. Might be worth looking in yours to see if there are any signs. I'd expect the 5am router reboot and the apparently sensitive Pi3 wifi module being responsible somehow.