Not sure if this just applies to the Checksum method, but performing a simulation run when the files already exist in the destination causes the NewItem names to be incorrect; that is, they're using their original file names rather than the new names they've been assigned.

Again, not sure if this is just the Checksum method plugin even though it does the same stuff as all the other methods.

The status of this issue can be tracked here on the FileSieve Github repository.