if Account manager
is online and server auto save or GM used /save
command then account changes from 111111
to 0
or any other random number then when players login to it server will crash.
Party system if 2 players kept spamming party invitation then leave party and both of them logged out after 5-6 times of spam server gonna crash.
Houses if no House-exit
set to them and an invited player logged out inside then owner left the house !leavehouse
and the logged inside player logs in server crash.
and much more which I can't remember right now that's why we advise everyone to move on and stop using old outdated engines/sources.