I have the same issue and don't know how to resolve it as well. I created a simple Tabular Regressor, dragged and dropped the .mlmodel file into Xcode as shown by HackingWithSwift (https://www.youtube.com/watch?v=554iAZE0Qq8). I tried all options for adding these files and I always get the same warning. Though, I can still use the trained model, it works but it just spams the debug area.

Hello Shimizu, Thank you so much for solving my problem in such a short time! It does the job perfectly and does not add complexity. Best wishes, Guillaume