Here is the reducer, the RemoveField function is removing the last element from the number of fields array instead of the passed index

const UiReducer = createSlice({
      name: 'ui',
      initialState: {
        name: 'User',
        numberOfFields: [0],
        numberOfSubFields: [0],
      },
      reducers: {
        setName(state, action) {
          state.name = action.payload;
        },
        AddField(state, action) {
          state.numberOfFields = [...state.numberOfFields, action.payload];
        },
        RemoveField(state, action) {
          console.log(action.payload);
          state.numberOfFields.splice(action.payload, 1);
        },
      },
    });