Exchange E-mail 3 Disappearing

[discdoc]

Is anyone else having the problem of their contacts' E-mail 3 disappearing? I notice that some of my contacts (the ones I contact regularly) that I have 3 e-mail addresses for, suddenly only have two. I can't seem to correlate it with anything. I re-enter the third e-mail address and within a few days it disappears again. Very Strange.