My REFGND is at GND and my REF is at 3.3V and the voltage across the resistors R2, R4 and R6 never be out of these limits. There flows current over R2, R4 and R6 resistors, it constitutes a voltage on this resistor and ADC read the voltage differentially. The voltage across this resistor is never being negative, and never being bigger than 3.3V. Always between 0V and 3.3V interval. The voltage across resistors are DC.
I will try a 100nF capacitance at IN+ and share the results with you.
Thank you.