1, baking time is really not enough. Because the baking time is not enough, the cake is just cooked as a whole, but the proportion of water in it is still relatively heavy. It was supposed to be baked for a while, but it ended early, which will also lead to it being in a relatively soft state.
2. Different batches of flour have different water absorption rates. Even if the same formula and proportion are used, it may lead to a little more liquid and easy. The batter is thin, and it will be soft inside when baking.
3. protein defoaming in the batter. Because this batch of cakes is waiting for the second baking, the protein bubbles inside will gradually defoam during this process. After defoaming, it can't be completely foamed when baking, and a lot of batter is piled up in the middle of the cake. That will also cause the center to be soft.
That's why the middle of the cupcake is not ripe. I believe that all of you have some understanding through the above, and I hope it will be useful to you.