Access - Insert query changing field names??

This is a weird problem I've never heard of before, hopefully I'll explain it ok.

I run an Insert query as part of a larger Access 2K app. It takes all the fields from the table XXX and inserts them into table XXXCombo (XXX can be any client code). The query gets built by matching field names between the tables. Since occasionally a field name can change and thus won't be matched up properly, before running the query I check the fields in design view to make sure they all match up.
The last field is called Comments. Now, just within the last two weeks, the field Comments in table XXX hasn't appeared in the top row of the query in design view because for some reason the bottom row, XXXCombo, is called Comment: (with a colon at the end). When I click the arrow in the top row, Comments is there, and I match them manually. When I do that, the bottom row then changes on its own to Comments to match the top.
If at any point I check the actual tables, the fields are always named Comments. These tables, different for each client, are imported from the server each time the app runs.
This isn't a fatal problem because I can fix it each time, but why would it happen, and why now?? Thanks.