I made dumplings from white flour and Atora vegetable suet. The suet is in hard pellets so I'm not worried about having overworked the mixture. I made them at the same time as the stew to save on wash-up. Then I stored them in the fridge for 4 hours before putting them in the pot for 20ish minutes. The pot was in the oven at 140C. They quickly puffed up and filled the top layer of the pot. But when cut open they had a different texture inside and (presumably) the taste of raw suet and flour. Is it likely the fridge or sitting time can explain the failure?
Edit: I still have some spares in the fridge and the pellets of suet are still visible in them. So I definitely did not overwork the dough.