Hi rdomain,   The comment above from "phil_m" is correct. It's not a problem with the Line 6 HX, but your Fender amp, (and some other brands also).   I recently spotted this comment in another forum regarding Fender amp switching: “As for nearly all newer Fender amps, the footswitch is a TS connected, switching voltage-levels on the same wire, which is interpreted by a logic circuit. Channel select and reverb transmit four different voltages.”   Maybe you will