a plane in 1945 would not likely be dropping a 1941 trop unless it had been sitting in storage for 3-4 years.
Sitting in storage for a couple of years might very well be what it did. There wasn't opportunity to use aerial torpedos every day. In fact I'll bet aerial torpedo attacks were a very rare occurance.
Plus the Japanese had a very hard time keeping their units supplied so older unused weapons and ammunition by be all they had hand.
Still newer versions available for the cyber war would be great.