Might there be a sort order specified for the relationship?
If so, you can remove that sort order or you can specify a sort order for your portal that keeps the portal rows in "creation order". Here's how: If you have not already done so, define a number field to auto enter a serial number. Specify a sort order for your portal to sort on that field in ascending order.
That was it, I had a sort order in the relationship which I have now removed.