Can't update garageband

I purchased a factory refurb Mac mini from the Apple Store a while ago. Recently, I was notified I had several updates, so I went to get them. Numbers, Keynote, and Pages updated fine, but GarageBand and Keynote refused to update, giving me the message "GarageBand cannot be updated because it was refunded or purchased with a different Apple ID." This is puzzling, as these apps were all the ones that came on the Mac mini when I purchased it, and I've always used this Apple ID on this machine.

Anybody have any insight on this?

MD