When you say turn-off and turn-on processes, do you mean the entire board, or just the switch and HC-05 module? Is there any big difference in power/signal lead length when you test the broken board?
According to the datasheet, it's well protected against over-current and over-temperature. The power switch also has a discharge function on the output, which has always seemed like asking for problems to me. Perhaps that HC-05 has much larger input capacitors than the others. You can try adding a diode to pass current from output to input, to suppress any inductive current spikes or large capacitive charges from anything on the HC-05 side.