Xcode 10 build error: 'must declare at least one output file'

I'm trying to get a somewhat complex application built with Xcode 10 so that I can submit it to the store shortly, and I am getting the following error (paths changed for simplicity reason).

Showing All Errors Only :-1: shell script build rule for '/Uses/Desktop/ios/app/Vendor/QMServices/QMContactListCache/QMContactListCache/CoreData/QMContactListModel.xcdatamodeld' must declare at least one output file (in target 'QMContactListCache')

I really have no clue what this means and I am not even sure how to find the target in the project as I don't see it. It builds in Xcode 9 no problems.

Any help would be appreciated.