Ran a 60/40 PA6/PET twill through a “3%” relax finish at 11:30 last night and it came back 7% shorter and mysteriously squeakier — my FEA and shrinkage model said I’d optimized for clown trousers… What’s your best tale of a perfectly reasonable material assumption turning into comedy during finishing or testing (extra credit if a Martindale or crock test did the roast)?