Postfix - main.cf changed for unknown reasons

Like i said in the title main.cf was changed for unknown reasons during server reboot. When i configured the virtual server, applied SSL, made few changes in main.cf i tested email several times with virtual server admin user and 2 more (in Usermin). Everything was perfect even connecting from Thunderbird was easy and without problems. Today i went to check my domain with mxtoolbox.com and i saw several (email) warnings what previously was not there (yesterday last time tested). Went to check the file and i saw immediately that the date was from today, maybe 1-2 hours before i notice the problem. Last time i edit this file was before 3 or 4 days and only thing what happened between yesterday (when the email was working) and today was one server restart (intentional from my side). Just to know this was not the first time server was rebooted in the last few days so if something was waiting to happen after the reboot it would happen way before.

This is part from maillog covering the time when was the server reboot:

Server restart was at 1:25 and before that aside of few failed attempt to connect from spam IP's (all rejected) nothing unusual. After that every restart of postfix gives this log (from maillog):

Messages log doesnt show anything unusual during the reboot. Later when mxtoolbox.com reported the errors i went to restart postfix and this is what i got from messages log:

** This 3 lines will repeat several times, usually from 3 to 5 more blocks of them:

Another thing, usermin cant send or receive emails and when i try to send i get this error:

Failed to send mail : Failed to connect to localhost:25 : Connection timed out

I tested port 25 with telnet and its open, i can connect to other mail servers without problem and from other location to my server:

All modifications done in main.cf are gone, e.g. it looks like from fresh install. From yesterday when the email was working up to the problem i didnt make any changes to postfix or anything else related to email.

Last but not least, this same problem i encounter before few months (5-6) when i was testing Vmin. To be honest after postfix imploded i just deleted entire server and ended my test. Now several months later i get same problem back. I try to modify main.cf but regardless of what i do the problem doesn't go away. Only way how to make email and Usermin to work again is to comment out this lines in master.cf (all of them):

But i checked master.cf (date, content) and it was not changed from the day i applied SSL (before 8-10 days) so i dont think something happen with this file. As I previously said if something was waiting for server restart to make changes it would happen before few days.

This is random bug poping out or somewhere is the trigger? I know postfix would not reset main.cf out of nowhere and it could be Vmin/Wmin related. Any ideas what is going on here?