You seem to be plotting 5 different transfer functions. You have to ask yourself what each of the 5 transfer functions represent. I bet when you do that you would see that there is no reason to believe they should be continuous.

PAC is a transfer function analysis. If you have some complicated input signal and you want to know how it is affected by your circuit. you would transform the input signal, multiply it by the transfer function, and the inverse transform it.

You would do that with only one of the transfer functions you have shown. Look at the output frequencies to determine which transfer function to use.

-Ken