[WMR] Unity keeps building for UWP in debug ???

I have a simple test project that I am trying to build for UWP, to display on a WMR headset on PC. The whole process is basically working, using the Build Window I can generate the project with IL2CPP backend and then build the appx version. I can also install the appx and run it fine. However it keeps building it in debug mode no matter what I do.

I checked in the build settings window that it is set to release (i even tried master), but I keep getting an appx in a folder named AppPackages/project_name/project_name_1.0.1.0_Debug_Test

I need to run this project on another machine but can't install it because of the dependency on MicrosoftVCLLibs.140.00 (which I never managed to resolve).

Has anyone had this issue ?
What do I need to do to build in release aside from setting it in the unity build settings ?

I'm running on pc, unity 2018.2 with the mixed reality toolkit from github.

Thanks !