Hello, I had the same issue when setting up a new environment using SoapUI 5.2.1. I have 3 different settings file for different with preferences for different release numbers.
Rolling back to SoapUI 5.0.0 has fixed it. Specifying the -t parameter with a setting file to use does not seem not to work with 5.2.1? Or is there a config somewhere that is required for it to function properly?