Thanks, David ...and yeah, I didn't think you would experience the issue because it rarely happens on another computer. I don't experience the issue either! ...However, I have seen numerous times where it does happen on the original machine where the join is attempted. Even so, it does not happen all the time with every computer. And, like I say, when the issue arises, it will only be the last record in the dataset that joins (state of Wyoming). If we're working with 'county' data, and the issue occurs, it will only join the last 14 counties in the dataset -- which are all in the state of Wyoming.
It's very odd; but, someone with a deep understanding of 'Joins and Indexing' might be able to figure out why this sometimes happens. ...Like I say, here is a fix (remove the Index on the common field), but I'm still really curious how this can happen in the first place.
Thanks, Craig