Ok, I remembered something from a similar discussion awhile back on another site...So I'm doing a web search right now, to come up with more specifics as to WHY this happened...

Anyways, in the previous discussion from researching then, I discovered alot about how simple it was to make bombs...How the simpliest ingredients could be used to make a rushed bomb, as well as bomb components that could easily be mistaken for the simplist everyday items/useages...

Peanutbutter was one of those. And the machines at the airports will zero in on peanutbutter, as well as maple syrup as bomb components...

So far, this is what I've found about the why:
What an Airport Bomb-Squad Chief Worries About | TIME

The machine has a tendency to go off when it encounters items like peanut butter and maple syrup, which mimic the characteristics of some explosives.

One of the searches I'm doing is for the list of over 3,000 useages of the peanut, including peanut butter done by Washington Carver. They just had a special on him on the history channel, of his research in uses for the peanut besides just eating...And some of those useages included fuels, vehicle parts, and plastics for bomb components as well...His research into the many uses still being studied and utilized today.