Disintegrating plastic bag

As with most households, we kept a substantial amount of plastic bags of various makes and sizes in the house. I had two huge black garbage bags that are filled to the brim with plastic bags. As I was packing to move into our new house and needed some large plastic bags, I rummaged through the stock pile to look for one. To my surprise, I found some J*sc* plastic bags having disintegrated among the stock pile. They've became really brittle and turned into pieces at the slightest touch. I can't even lift a single piece of the plastic bags out and they literally became a mass of dust inside the black garbage bag. I dismissed the incidence and thought that they must have been produced among a poorly manufactured batch.

I experienced it the second time when packing a set of new bed sheet which hubby bought at J*sc* Card members' sale last year. We've kept the bed sheet aside in the original J*sc* plastic bag after purchasing it as we planned to use it only at the new house. When I lifted the bed sheet, the plastic bag crumbled into pieces. Two incidences within the same day don't make a co-incidence, does it?