No, the map is constantly saving, however if some sort of hacking problems were to arise, the "map saving" is taking a copy of the map to put in another location. if C were to crash, it should not loose more than a minutes worth of work, unless the server was once again hanging, but players remain able to interact client side(which happens right before these mysterious crashes.) As far as I can tell its the same problem we were having 2 years ago, where chat on the server worked perfectly, but placing blocks does not.