Gain of filter is higher than calculated - why?
The transfer function is

$$H(s)=\frac{-sR_1C_2}{1+s(R_1C_1+R_2C_2)+s^2R_1R_2C_1C_2}$$

and the maximum gain is

$$A_{\text{max}}=\frac{R_1C_2}{R_1C_1+R_2C_2}=2.04$$