My son bought me a Keurig a couple years ago. It worked well until recently, when it started blowing the cups out. It seems to affect the tinfoil lids the most. Pressure builds up, until the lid splits around the perforator..then it put coffee grounds throughout the catch mug.
I can normally avoid the pressure buildup, if when I place the Keurig cup in the machine , I turn it and perforate the bottom of the cup 3-4 times.
I'm gradually switching back to my old 4 cup, Mr Coffee machine..