The overpressure condition is caused by the inner filter popping, leaking grounds and clogging the bottom needle. The water being pumped by the coffee maker has nowhere to go so the pressure is enough to pop the top seal. I cut open some different pods to see the construction of them. I found that the Starbucks brand has an added filter shield under the filter pod. It has holes to allow the coffee to go through, but supports the filter pod from popping. I also found that many brands of pods have a larger filter pod inside. The larger filter pod hangs low enough that the bottom needle of the coffee maker can pierce the filter and cause it to leak grounds.