Estes 13mm Date Code Warning

Hm. I feel like I may have been instrumental in pushing this one to the point of Estes issuing an official alert via email. I had an A3-4T with date code H21 0921 cook one of my rockets at the last launch. I reported it and just got the shipping notice for a replacement pack earlier today. Just now I got the email with the warning seen below. I'd also files a mess report and about 3/4 of the reports on A3-4Ts in the last two years were this date code.