Can you tell me what Sainsburys have done to change their shortcrust pastry?

Getting food ready for friends to come round to eat, I prepared some of your pastry as I have many times before.

I blind baked it and it shrunk to a flat piece of flobby pastry, the sides do usually shrink a little but not to the point that they disappear, rather than make my own, I thought, to save time I would pop out and buy some more.

Again with the same conditions as I always have, same dish, same oven, same temperature, it did the same.
Eventually now well behind time and somewhat stressed I made my own.

What have you done to the recipe?
Whatever you’ve done it doesn’t work, except probably to make you more money.
I am one customer who will no longer buy it…
Anyone else had this problem?