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ADP124 passing 4.5V to output

I've run into a strange problem with an ADP124 3.3V regulator.  I have a design that has a 5V rail that is used to power the ADP124 regulator as well as an ADR130 1V Reference.  The output of the ADR130 is sent to a MAX5482 Digital pot.  The wiper of the digital pot feeds a source with a 1M input impedance.  When I set the digital pot to about halfway through it's range (producing approximately 0.5 on the wiper) the ADP124 craps out and then starts passing about 4.4 - 4.5 of DC.  Both the MAX5482 and the ADR130 are powered by the 5V rail.  I don't see any current spikes or anything of that nature on 5V rail when it happens.  If I adjust the pot so that the wiper voltage is lowered to less than 0.5V the 3.3V rail comes back into regulation.  I'm about out of ideas, I'm really at a loss any thoughts or troubleshooting suggestions would be appreciated.