Importing - more than 1 match in the source file can mean more than one record in the target file
We've recently converted from v6 to v9 and hoped to continue to do importing as we had done previously. Generally, we import from xls files matching on one field and adding remaining data as new records. Where more than 1 record in the source file had a match in the target file, the record in the target file was updated with the last matching record in the source file, which was just what we needed.
I've imported a couple of times now into v9, and find that on some occasions (not all), if there is more than one match in the source file, more than 1 record is created in the target file. To date, the duplicates have appeared for data that did not previously have a match in the target file, but there was some of this sort of data that did not lead to duplicates.
Suggestions as to what I'm doing wrong and/or am overlooking would be much appreciated please. Or perhaps v9 handles imports of this kind differently to the way v6 did???