MAX471 giving too high current readings
Do you have the same operating circuit that is shown on page 1 of the datasheet? do you have the 2K resistor they specifically from OUT to ground? Also, it may be worth adding the 1 uF capacitor they recommend from OUT to ground too
The other thing to consider is the actual voltage over the resistor. Check an see if the voltage over the resistor is 3.3 and that there isn't a voltage drop from the chip
If the voltage is fine, there may be a problem with the chip or the arduino