Micro has this pull-down resistor inside, which is able to force low state at output of DS1232, even if output low driver transistor of DS1232 is damaged. So, when DS1232 is connected to micro low state is ok, but if disconnected to micro damaged output low driver transistor of DS1232 cannot pull the output down.

If this is the case can easily be tested: Connect a 47kOhm resistor from reset pin of DS1232 to ground. If now the potential goes down to 0V, then internal NMOS transistor of output stage of DS1232 had been 'toasted' with experimenting.

Kai