Can't confirm it but it wouldn't surprise me - that's exactly how the dud torpedoes work, and I strongly suspect the dice are loaded.
Latest numbers seem to be working okay, instead of half a dozen escorts blowing their own fantails off in a single battle I had only one during an entire patrol pull the Barney Fife - creeping along at 3 knots and rolling a shallow charge off the side rack was a bad idea in real life too. They don't have to be cranking along at full tilt boogie to escape the blast effects either, any reasonable speed will keep them clear. And my sub don't get away scot free 50 yards outside the pattern, there's some minor damage, and it's cumulative too - dozens of near misses do the same damage over time as a hit. Not very scientific, but it just FEELS more realistic to me.