EXS 24 Logic Sampler Users Group

I have an annoying problem that keeps reoccurring.

I work on a song, and upon completion, I make sure that the 
program is saved as well as the song.
When the song is reloaded, sometimes the program is recalled 
correctly, but sometimes the wrong sound is called up.

luckily i can remember what it should have been, so no major 
harm is done, but it is an annoying problem.

BTW, it seems to always load the same program (the wrong 
one, but the same wrong one if you see what I mean.)

Anybody got any ideas why this is happening?

David T