combo box problem

This is really strange. I have a combo box which I fill with a list of companies. The combo box has 4 columns. Out of ~250 records, there are a handful that it will not find.

Let me be more precise. The companies and related fields show in the combo box. When you select them, it does not hold that column's fields. With all the other companies, when you select the company you can then use the combo box columns property and get the appropriate values. Not so with this hand full of companies. I have looked at the values and I can use the same query in SQL (it's tables are linked SQL tables) and it finds the value correctly. I don't think the data in the table is incorrect. I just don't understand why Access isn't holding this data as selected.

I know it isn't, because if I select one of the problem companies, tab out of the combo box and then reselect the combo box, it's pointing to the first value in the list. If I do this same thing to other companies, it holds the value of that record as the selected record.

Any help would be greatly appreciated. I've looked at this until I'm blue in the face and can't figure out what's happening.