Unable to switch materials in the extruders

[AlessandroCorsini 0]

Good morning, I have a problem with Cura (version 4.13.1). I'm printing a bimaterial sample but I cannot switch materials from extruder 1 to extruder 2. Let's explain better: If I select Alumina in the extruder 1 and Steel in the extruder 2 and I slice, the preview is as I want. If I select Steel in extruder 1 and Alumina in extruder 2, in the preview my project is not as I want. 

What's the problem?

I attach the .3mf and the .stl project to better understand

 PAMHT_Al2O3_316L.3mf

 

 

 

 

 

 

 

[ahoeben 1,992]

Please attach a project file, so we get both the model AND your settings. I know this might be confusing, but if you use File -> Save project... you also create a 3mf file, but that 3mf file contains more information.

 

Without the project file, and with no description to go with your screenshots, I can only guess that the "yellow" material has the setting "Remove all holes" enabled, whereas the "green" material does not.

[AlessandroCorsini 0]

PAMHT_Al2O3_316L_V2.3mf

This is the .3mf file 

[Slashee_the_Cow 443]

You appear to be using a custom machine definition - you'll have to put the file/s for that inside a zip file and post it here for us to be able to open your project as a project rather than just loading the models.