Look at Amux_1 input number 1. This signal is connected to the other mux Amux_3 input number 0. So this signal is connected to two (2) inputs but no signal drives it.
Are the Amuxes asymmetric? In principle, the Pin5 current would drive input 1back into Amux3 and then to the buffer and SAR. I guess I'm looking at this conceptually as a bidirectional attachment.
jasonkahana, Analog Mux inputs can only connect to input terminals, nothing else. Use modulators internally. To invert polarity use ADC_DelSig in differential mode + modulation Input.