TPS71701DCK problem

I am using this adjustable version of the TPS717xx series of linear regulators in a circuit that matches the datasheet - 1uF input cap, 1uF output cap, feedback resistors of 576K or 590K on top and 158K on the bottom (close to the requested 160K). These are all 1% resistors. The input voltage is 4V. The output current is very low - about 50uA. For the values given, I should get output voltages of either 3.71V or 3.78V. However, with the 576K resistor, the output stays below 3.7V and I have an example that has an output of 3.604V. Using the 590K yielded a circuit that would sometimes read higher than 3.7V, but the output was erratic and changed wildly when I tested the part between 30C and 60C ambient temperatures. I did not try to take it to our low temperature minimum of -40C. Adding a load to the part did not help. The datasheet states that the part should be stable with no load and that the dropout voltage is 300mV MAXIMUM. Increasing the input voltage to 4.2V did not help, either. The part seems completely unpredictable in this configuration. Is there something I am doing wrong? It really doesn't look like it...