All pc's in a network shutting down during a specific time stamp

Well i am in charge of troubleshooting and fixing a,network consisted of 100 devices (pc's)approx And a weird think keeps happening each day, the pc's turn off at around 1:16 some at 1:17 and some at 1:18 Not all at the same time which made me lost I don't have pc autoshutdown or wake on lan scheduled shutdown at that time What i tried to do to fix it but couldn't fix it: -Formatted a lot of them and re installed windows -Ran wireshark on it to check if its receving any packets from wake on lan or remote shutdown to shutdown couldn't find any _ checked event viewer to check event's before the pc's shutdown and also couldn't find anything related

Note: -all the pc's are part of a single domain _no faulty hardware from pc side for sure