LP5907: Turn on transient seems excessive

We are attempting to use an LP5907 to supply 1.8 Volts to the chips that need it from an onboard 3.3v supply whose output rises at a controlled rate of about 1V/ms, See scope shot #1. When the 3.3 input gets to about 1 V the output of the 5907 rises suddenly to about 1 v (event 1) and then stays there about 200 us until the 3.3 reaches about 2.4 or so volts.At that point the output of the 5907 starts to follow the 3.3v up to its final value of 1.8 V. I had kind of expected the 5907 output to follow the linearly rising 3.3V at event 1. I attempted to smooth out the 1.8V output by trying to use the EN pin as a kind of soft start by putting a resistor from it to the 3.3V input  with a capacitor to ground, starting with 10K and .1uF, the idea being to delay the enable pin until the 3.3 had reached its ultimate value. See scope shot #2. This did not work as planned although it did affect the output. See scope shot #3. After looking more closely at the data sheet I noticed a POR circuit whose operation is not fully explained. I wonder if this POR is the source of the roughly 1 ms delay from the start of the input voltage rise to event 1. Is there a minimum rise time for the input that I have missed? My input and output capacitors are both 0.1uF XZR. I also noticed in figures 15 and 16 of the data sheet that there are glitches similar to my event 1 but they happen much quicker (20 us) which may be due to Vin being applied with a faster rise time than ours. Should I speed up our rise time?