Yeah, sure. But I admit I have no idea how long sub patrols were in the early days. What I am trying to put forward is the views at the time. With 20-20 hindsight, we all know what should have happened. But how many sub patrols by the newer subs, (and I don't recall any of them being in the Philippines at the time. I am probably wrong on this), carry out ITTL at this stage.
The main USN Sub base would by now be Pearl. What is the transit time from Pearl to the patrol zones, how long were they expected to remain on station and then how long back to Pearl? A month, two?
Then write up AARs, where a number of apparent misfires, failed firing solutions, etc are highlighted? Then allow the HQs to do the OTL thing of accusing the sub captains of not pressing attacks hard enough, inexperience using equipment, stress under operational conditions leading to poor tactical decisions. etc. So refuel, rearm, resupply and out on another patrol.
Having worked with Defence Bureaucrats in the past, an immediate realisation that there must be something wrong with the equipment is not the immediate answer.
So what I am trying to say is that it will inevitably take a couple of sub patrols by the newer subs before someone smells a rat, even if it is merely the sub commanders. After all, not every firing solution works. The target can change course, change speed, etc that will negate even the best firing solution. So how long are the patrols and how many of them are needed before the penny drops? This could take quite a few months before anyone connects the dots that we know.
Great points.
The Germans took a long while to fix their torpedoes, too - they weren't working properly until December 1942. http://www.uboataces.com/articles-wooden-torpedoes.shtml
The fact that the Germans also took a while to realise they has a problem, and even longer to fix it, indicates that (as you say) it's harder to work out that there's a problem in real life than when we read about the issues decades later, and harder to fix it. I hacen't had a chance to read this thesis about the issues with German torpedoes (https://digitalcommons.georgiasouthern.edu/cgi/viewcontent.cgi?article=1599&context=etd).
To underline the extent of similar issues, some of the earliest examples of German torpedo malfunction took place during the same action as the earliest examples of the failure of the British anti-submarine bomb. Given what munitions have to go through, it's probably not surprising that all combatants had major problems with duds during WW2,