Can a record be SELECTed twice in sort/selection processing?

[Boaz Bezborodko]

If a sort/select program somehow sees and selects a record twice during 
it's processing, does that mean that the record will now appear twice to 
the output processing?

I think this happened in one of my programs, but I'm not sure if that's 
what I'm looking for or not.  An answer to this will help me nail down 
the source of the problem.

Thanks,

Boaz