I have initialized all unused interrupts in the following way:

void int_0 (void) interrupt 0 using 0{}
void int_2 (void) interrupt 2 using 0{}
void int_3 (void) interrupt 3 using 0{}
void int_5 (void) interrupt 5 using 0{}
void int_6 (void) interrupt 6 using 0{}
void int_7 (void) interrupt 7 using 0{}
void int_8 (void) interrupt 8 using 0{}
void int_9 (void) interrupt 9 using 0{}
void int_10 (void) interrupt 10 using 0{}
void int_11(void) interrupt 11 using 0{}
void int_12 (void) interrupt 12 using 0{}
void int_13 (void) interrupt 13 using 0{}
void int_14 (void) interrupt 14 using 0{}
void int_15 (void) interrupt 15 using 0{}
void int_16 (void) interrupt 16 using 0{}
void int_17 (void) interrupt 17 using 0{}
void int_18 (void) interrupt 18 using 0{}
void int_19 (void) interrupt 19 using 0{}
void int_20 (void) interrupt 20 using 0{}
void int_21 (void) interrupt 21 using 0{}
void int_22 (void) interrupt 22 using 0{}
void int_23 (void) interrupt 23 using 0{}
void int_24 (void) interrupt 24 using 0{}
void int_25 (void) interrupt 25 using 0{}
void int_26 (void) interrupt 26 using 0{}
void int_27 (void) interrupt 27 using 0{}
void int_28 (void) interrupt 28 using 0{}
void int_29 (void) interrupt 29 using 0{}
void int_30 (void) interrupt 30 using 0{}
void int_31 (void) interrupt 31 using 0{}

After two hours the interrupt from Timer 0 is stuck again..