Look at where the failure initiates. Delamination that starts in the print field, away from seals — especially if it correlates with a recent ink or film change — points toward substrate-ink incompatibility or a surface energy gap. Delamination that starts at or near the seal, or shows up as channel leaks and weak peel, points toward heat-seal parameters (temperature, pressure, dwell) or a sealant-to-fill mismatch. Logging the failure location and the associated SKU, shift, and substrate lot is the fastest way to separate the two.